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Forum Update on Monday, May 27th 2025

qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.

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  • JonBJ JonB

    @mywings19 said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

    Then I've set 'export QT_DEBUG_PLUGINS=1'
    but there's no extra error message,qtcreator is running normally

    Have you actually run whatever executable raises the error (Qt Creator itself?? Your application?) from the shell where you set this environment variable, like all the posts tell you to? Because if so you should get a whole bunch of diagnostic output lines....

    M Offline
    M Offline
    mywings19
    wrote on last edited by
    #134

    @JonB

    sugon@EC:~$ cat ~/.bashrc
    # ~/.bashrc: executed by bash(1) for non-login shells.
    # see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
    # for examples
    
    # If not running interactively, don't do anything
    case $- in
        *i*) ;;
          *) return;;
    esac
    
    # don't put duplicate lines or lines starting with space in the history.
    # See bash(1) for more options
    HISTCONTROL=ignoreboth
    
    # append to the history file, don't overwrite it
    shopt -s histappend
    
    # for setting history length see HISTSIZE and HISTFILESIZE in bash(1)
    HISTSIZE=1000
    HISTFILESIZE=2000
    
    # check the window size after each command and, if necessary,
    # update the values of LINES and COLUMNS.
    shopt -s checkwinsize
    
    # If set, the pattern "**" used in a pathname expansion context will
    # match all files and zero or more directories and subdirectories.
    #shopt -s globstar
    
    # make less more friendly for non-text input files, see lesspipe(1)
    #[ -x /usr/bin/lesspipe ] && eval "$(SHELL=/bin/sh lesspipe)"
    
    # set variable identifying the chroot you work in (used in the prompt below)
    if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
        debian_chroot=$(cat /etc/debian_chroot)
    fi
    
    # set a fancy prompt (non-color, unless we know we "want" color)
    case "$TERM" in
        xterm-color|*-256color) color_prompt=yes;;
    esac
    
    # uncomment for a colored prompt, if the terminal has the capability; turned
    # off by default to not distract the user: the focus in a terminal window
    # should be on the output of commands, not on the prompt
    #force_color_prompt=yes
    
    if [ -n "$force_color_prompt" ]; then
        if [ -x /usr/bin/tput ] && tput setaf 1 >&/dev/null; then
            # We have color support; assume it's compliant with Ecma-48
            # (ISO/IEC-6429). (Lack of such support is extremely rare, and such
            # a case would tend to support setf rather than setaf.)
            color_prompt=yes
        else
            color_prompt=
        fi
    fi
    
    if [ "$color_prompt" = yes ]; then
        PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
    else
        PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '
    fi
    unset color_prompt force_color_prompt
    
    # If this is an xterm set the title to user@host:dir
    case "$TERM" in
    xterm*|rxvt*)
        PS1="\[\e]0;${debian_chroot:+($debian_chroot)}\u@\h: \w\a\]$PS1"
        ;;
    *)
        ;;
    esac
    
    # enable color support of ls and also add handy aliases
    if [ -x /usr/bin/dircolors ]; then
        test -r ~/.dircolors && eval "$(dircolors -b ~/.dircolors)" || eval "$(dircolors -b)"
        alias ls='ls --color=auto'
        #alias dir='dir --color=auto'
        #alias vdir='vdir --color=auto'
    
        #alias grep='grep --color=auto'
        #alias fgrep='fgrep --color=auto'
        #alias egrep='egrep --color=auto'
    fi
    
    # colored GCC warnings and errors
    #export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'
    
    # some more ls aliases
    #alias ll='ls -l'
    #alias la='ls -A'
    #alias l='ls -CF'
    
    # Alias definitions.
    # You may want to put all your additions into a separate file like
    # ~/.bash_aliases, instead of adding them here directly.
    # See /usr/share/doc/bash-doc/examples in the bash-doc package.
    
    if [ -f ~/.bash_aliases ]; then
        . ~/.bash_aliases
    fi
    
    # enable programmable completion features (you don't need to enable
    # this, if it's already enabled in /etc/bash.bashrc and /etc/profile
    # sources /etc/bash.bashrc).
    if ! shopt -oq posix; then
      if [ -f /usr/share/bash-completion/bash_completion ]; then
        . /usr/share/bash-completion/bash_completion
      elif [ -f /etc/bash_completion ]; then
        . /etc/bash_completion
      fi
    fi
    # Set LS_COLORS environment by Deepin
    if [[ ("$TERM" = *256color || "$TERM" = screen* || "$TERM" = xterm* ) && -f /etc/lscolor-256color ]]; then
        eval $(dircolors -b /etc/lscolor-256color)
    else
        eval $(dircolors)
    fi
    
    export QT_DEBUG_PLUGINS=1
    export QT_QPA_PLATFORM_PLUGIN_PATH=/home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms
    sugon@EC:~$ source ~/.bashrc
    sugon@EC:~$ ~/Software/qtcreator8.0.1/bin/qtcreator
    sugon@EC:~$ ~/QtProject/build-Test-Qt_6_3_1_in_PATH_Qt6_3_1-Debug/Test
    qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "/home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms" even though it was found.
    This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
    
    Available platform plugins are: linuxfb, minimal, offscreen, vnc, eglfs, minimalegl, vkkhrdisplay, wayland-egl, wayland, xcb.
    
    Aborded
    sugon@EC:~$ ldd ~/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/libqxcb.so 
            linux-vdso.so.1 (0x00007ffeb7df5000)
            libQt6XcbQpa.so.6 => /home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/../../lib/libQt6XcbQpa.so.6 (0x00007fd7162df000)
            libxkbcommon-x11.so.0 => /lib/x86_64-linux-gnu/libxkbcommon-x11.so.0 (0x00007fd7162b0000)
            libxkbcommon.so.0 => /lib/x86_64-linux-gnu/libxkbcommon.so.0 (0x00007fd71626e000)
            libxcb-icccm.so.4 => /lib/x86_64-linux-gnu/libxcb-icccm.so.4 (0x00007fd716267000)
            libxcb-image.so.0 => /lib/x86_64-linux-gnu/libxcb-image.so.0 (0x00007fd716261000)
            libxcb-keysyms.so.1 => /lib/x86_64-linux-gnu/libxcb-keysyms.so.1 (0x00007fd71625c000)
            libxcb-randr.so.0 => /lib/x86_64-linux-gnu/libxcb-randr.so.0 (0x00007fd716248000)
            libxcb-render-util.so.0 => /lib/x86_64-linux-gnu/libxcb-render-util.so.0 (0x00007fd716241000)
            libxcb-shm.so.0 => /lib/x86_64-linux-gnu/libxcb-shm.so.0 (0x00007fd71623c000)
            libxcb-sync.so.1 => /lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007fd716232000)
            libxcb-xfixes.so.0 => /lib/x86_64-linux-gnu/libxcb-xfixes.so.0 (0x00007fd716228000)
            libxcb-render.so.0 => /lib/x86_64-linux-gnu/libxcb-render.so.0 (0x00007fd716219000)
            libxcb-shape.so.0 => /lib/x86_64-linux-gnu/libxcb-shape.so.0 (0x00007fd716212000)
            libxcb-xkb.so.1 => /lib/x86_64-linux-gnu/libxcb-xkb.so.1 (0x00007fd7161f4000)
            libxcb.so.1 => /lib/x86_64-linux-gnu/libxcb.so.1 (0x00007fd7161ca000)
            libQt6OpenGL.so.6 => /home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/../../lib/libQt6OpenGL.so.6 (0x00007fd716128000)
            libQt6Gui.so.6 => /home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/../../lib/libQt6Gui.so.6 (0x00007fd7157a5000)
            libGL.so.1 => /lib/x86_64-linux-gnu/libGL.so.1 (0x00007fd715711000)
            libQt6Core.so.6 => /home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/../../lib/libQt6Core.so.6 (0x00007fd7150ac000)
            libX11-xcb.so.1 => /lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007fd7150a7000)
            libX11.so.6 => /lib/x86_64-linux-gnu/libX11.so.6 (0x00007fd714f66000)
            libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fd714f61000)
            libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fd714f40000)
            libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007fd714dbc000)
            libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fd714c37000)
            libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007fd714c1d000)
            libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fd714a5c000)
            libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007fd71493d000)
            libgthread-2.0.so.0 => /lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007fd714938000)
            libxcb-util.so.0 => /lib/x86_64-linux-gnu/libxcb-util.so.0 (0x00007fd71492c000)
            libXau.so.6 => /lib/x86_64-linux-gnu/libXau.so.6 (0x00007fd714927000)
            libXdmcp.so.6 => /lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007fd71491f000)
            libEGL.so.1 => /lib/x86_64-linux-gnu/libEGL.so.1 (0x00007fd71490a000)
            libfontconfig.so.1 => /lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007fd7148c4000)
            libQt6DBus.so.6 => /home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/../../lib/libQt6DBus.so.6 (0x00007fd7147f2000)
            libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007fd7147d5000)
            libfreetype.so.6 => /lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007fd714719000)
            libGLX.so.0 => /lib/x86_64-linux-gnu/libGLX.so.0 (0x00007fd7146e5000)
            libGLdispatch.so.0 => /lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007fd714628000)
            libicui18n.so.56 => /home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/../../lib/libicui18n.so.56 (0x00007fd71418d000)
            libicuuc.so.56 => /home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/../../lib/libicuuc.so.56 (0x00007fd713dd5000)
            libicudata.so.56 => /home/sugon/Software/qtcreator8.0.1/lib/Qt/plugins/platforms/../../lib/libicudata.so.56 (0x00007fd7123f2000)
            librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fd7123e8000)
            /lib64/ld-linux-x86-64.so.2 (0x00007fd716397000)
            libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007fd712374000)
            libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007fd71235a000)
            libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007fd71231b000)
            libuuid.so.1 => /lib/x86_64-linux-gnu/libuuid.so.1 (0x00007fd712312000)
            libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007fd7122bf000)
            libpng16.so.16 => /lib/x86_64-linux-gnu/libpng16.so.16 (0x00007fd712286000)
            libXext.so.6 => /lib/x86_64-linux-gnu/libXext.so.6 (0x00007fd712271000)
            libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007fd7121ce000)
            liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007fd7121a6000)
            liblz4.so.1 => /lib/x86_64-linux-gnu/liblz4.so.1 (0x00007fd712187000)
            libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007fd712062000)
            libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007fd71203f000)
    sugon@EC:~$ 
    
    1 Reply Last reply
    0
    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #135

      Hi,

      Why are you pointing the plugin path to Qt Creator's installation rather than the Qt version you used to build your application ?

      By default you should not even need to use that variable.

      Interested in AI ? www.idiap.ch
      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

      M 1 Reply Last reply
      0
      • SGaistS SGaist

        Hi,

        Why are you pointing the plugin path to Qt Creator's installation rather than the Qt version you used to build your application ?

        By default you should not even need to use that variable.

        M Offline
        M Offline
        mywings19
        wrote on last edited by
        #136

        @SGaist
        Me?That might be the problem

        When I point the Qt plugin path, 'xcb' couldn't be found
        sugon@EC:~$ ~/QtProject/build-Test-Qt_6_3_1_in_PATH_Qt6_3_1-Debug/Test
        qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in "/home/sugon/Software/Qt6.3.1/plugins/platforms/"
        This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
        Available platform plugins are: linuxfb, minimal, offscreen, vnc.

        So shall I reinstall the Qt or add some plugins?
        Thank you

        1 Reply Last reply
        0
        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #137

          Start your application with the QT_DEBUG_PLUGINS environment variable set to 1 to see why the loading fails.

          Interested in AI ? www.idiap.ch
          Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

          M 1 Reply Last reply
          1
          • SGaistS SGaist

            Start your application with the QT_DEBUG_PLUGINS environment variable set to 1 to see why the loading fails.

            M Offline
            M Offline
            mywings19
            wrote on last edited by mywings19
            #138

            @SGaist said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

            Start your application with the QT_DEBUG_PLUGINS environment variable set to 1 to see why the loading fails.

            I've set the QT_DEBUG_PLUGINS environment variable in the .bashrc file and sourced it. See floor.134
            But these is no error message while loading qtcreator.

            sugon@EC:~$ echo $QT_DEBUG_PLUGINS
            1
            sugon@EC:~$

            1 Reply Last reply
            0
            • hskoglundH Online
              hskoglundH Online
              hskoglund
              wrote on last edited by
              #139

              Hi, perhaps you are launching Qt Creator by double clicking on it?
              If so, instead try starting Qt Creator from the same Terminal window that has QT_DEBUG_PLUGINS set to 1.

              M 1 Reply Last reply
              0
              • hskoglundH hskoglund

                Hi, perhaps you are launching Qt Creator by double clicking on it?
                If so, instead try starting Qt Creator from the same Terminal window that has QT_DEBUG_PLUGINS set to 1.

                M Offline
                M Offline
                mywings19
                wrote on last edited by
                #140

                @hskoglund said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

                Hi, perhaps you are launching Qt Creator by double clicking on it?
                If so, instead try starting Qt Creator from the same Terminal window that has QT_DEBUG_PLUGINS set to 1.

                Thank you, but I always start qtcreator in terminal. It can be seen in floor.134

                sugon@EC:~$ source ~/.bashrc
                sugon@EC:~$ ~/Software/qtcreator8.0.1/bin/qtcreator
                sugon@EC:~$ ~/QtProject/build-Test-Qt_6_3_1_in_PATH_Qt6_3_1-Debug/Test

                There's no error message until I closed the software.

                JonBJ 1 Reply Last reply
                0
                • M mywings19

                  @hskoglund said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

                  Hi, perhaps you are launching Qt Creator by double clicking on it?
                  If so, instead try starting Qt Creator from the same Terminal window that has QT_DEBUG_PLUGINS set to 1.

                  Thank you, but I always start qtcreator in terminal. It can be seen in floor.134

                  sugon@EC:~$ source ~/.bashrc
                  sugon@EC:~$ ~/Software/qtcreator8.0.1/bin/qtcreator
                  sugon@EC:~$ ~/QtProject/build-Test-Qt_6_3_1_in_PATH_Qt6_3_1-Debug/Test

                  There's no error message until I closed the software.

                  JonBJ Online
                  JonBJ Online
                  JonB
                  wrote on last edited by
                  #141

                  @mywings19 said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

                  There's no error message until I closed the software.

                  In that case when does the message you showed earlier:

                  qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in "/home/sugon/Software/Qt6.3.1/plugins/platforms/"
                  This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
                  Available platform plugins are: linuxfb, minimal, offscreen, vnc.
                  

                  appear? Not until after you close Creator? Interesting.....

                  M 1 Reply Last reply
                  0
                  • JonBJ JonB

                    @mywings19 said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

                    There's no error message until I closed the software.

                    In that case when does the message you showed earlier:

                    qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in "/home/sugon/Software/Qt6.3.1/plugins/platforms/"
                    This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
                    Available platform plugins are: linuxfb, minimal, offscreen, vnc.
                    

                    appear? Not until after you close Creator? Interesting.....

                    M Offline
                    M Offline
                    mywings19
                    wrote on last edited by mywings19
                    #142

                    @JonB said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

                    @mywings19 said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

                    There's no error message until I closed the software.

                    In that case when does the message you showed earlier:

                    qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in "/home/sugon/Software/Qt6.3.1/plugins/platforms/"
                    This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
                    Available platform plugins are: linuxfb, minimal, offscreen, vnc.
                    

                    appear? Not until after you close Creator? Interesting.....

                    This 3 line message is showed when I build and run a test project.
                    I mean after I set QT_DEBUG_PLUGINS to 1, There's no extra error message except this 3 line when I start qtcreator or run project in terminal.

                    Now, I've uninstall the Qt and qtcreator,then installing by online installer.

                    1 Reply Last reply
                    0
                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #143

                      Is that a custom Qt build ? Because from the looks of it, the plugin is indeed not there.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

                      1 Reply Last reply
                      0
                      • B Offline
                        B Offline
                        BenyaminZojaji
                        wrote on last edited by
                        #144

                        In my case, I just upgrade PyQt5 to PyQt6 and that works.

                        1 Reply Last reply
                        0
                        • T trimixotun

                          It's looks slightly outdated, but maybe it someone helps:

                          1. Debian 10 x86-64.
                          2. LXDE
                          3. Fresh net install Qt 5.12.10

                          Qtcreator first launch problem: "qt.qpa.plugin: Could not load the Qt platform plugin "xcb"".

                          Nothing from above helps at all. Qtcreator needs libxcb-util.so.1, but system has only libxcb-util.so.

                          Simple solution:

                          sudo ln -s /usr/lib/x86_64-linux-gnu/libxcb-util.so /usr/lib/x86_64-linux-gnu/libxcb-util.so.1

                          All work, folks.

                          G Offline
                          G Offline
                          GEZawaTT
                          wrote on last edited by
                          #145

                          @trimixotun this worked!! Thank you so much!

                          1 Reply Last reply
                          0
                          • 3 Offline
                            3 Offline
                            3mad
                            wrote on last edited by
                            #146

                            In my case, I had the issue when installing ParaView, things fixed by installing the libxcb-xinput0 package:
                            sudo apt-get install libxcb-xinput0

                            Then, things work fine.

                            1 Reply Last reply
                            0
                            • R Offline
                              R Offline
                              roux.benoit
                              wrote on last edited by
                              #147

                              Hi,

                              I know this is an old post, but I have the same issue that comes up when I'm setting some path for the LD_Library_path.

                              for the context i'm creating a container that run an app with a gui using pyqt5, which works perfectly.

                              However, I also need to install matlab runtime and after I set up Matlab runtime environement path :

                              LD_LIBRARY_PATH=/opt/mscr/v912/runtime/glnxa64:/opt/mcr/v912/bin/glnxa64:/opt/mcr/v912/sys/os/glnxa64:/opt/mcr/v912/sys/opengl/lib/glnxa64

                              the gui stops working and I get the "qt.qpa.plugin ..." error message.

                              Any thoughts?
                              Thanks a lot

                              SGaistS 1 Reply Last reply
                              0
                              • R roux.benoit

                                Hi,

                                I know this is an old post, but I have the same issue that comes up when I'm setting some path for the LD_Library_path.

                                for the context i'm creating a container that run an app with a gui using pyqt5, which works perfectly.

                                However, I also need to install matlab runtime and after I set up Matlab runtime environement path :

                                LD_LIBRARY_PATH=/opt/mscr/v912/runtime/glnxa64:/opt/mcr/v912/bin/glnxa64:/opt/mcr/v912/sys/os/glnxa64:/opt/mcr/v912/sys/opengl/lib/glnxa64

                                the gui stops working and I get the "qt.qpa.plugin ..." error message.

                                Any thoughts?
                                Thanks a lot

                                SGaistS Offline
                                SGaistS Offline
                                SGaist
                                Lifetime Qt Champion
                                wrote on last edited by
                                #148

                                @roux-benoit hi,

                                Check whether there's Qt libraries in your matlab installation.

                                Interested in AI ? www.idiap.ch
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                                0
                                • P Offline
                                  P Offline
                                  phil-lipp
                                  wrote on last edited by
                                  #149

                                  I hope someone on this forum can help me. I'm trying to use Howdy (https://github.com/boltgolt/howdy), but I get the error described by OP.
                                  I only get the error when I use su -, however when I use plain su (without the -) it works. So I think i somehow messed up the install when I forgot to add the -... how can I fix this?

                                  the error:

                                  qt.qpa.xcb: could not connect to display 
                                  qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
                                  This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
                                  ``
                                  JonBJ 1 Reply Last reply
                                  0
                                  • P phil-lipp

                                    I hope someone on this forum can help me. I'm trying to use Howdy (https://github.com/boltgolt/howdy), but I get the error described by OP.
                                    I only get the error when I use su -, however when I use plain su (without the -) it works. So I think i somehow messed up the install when I forgot to add the -... how can I fix this?

                                    the error:

                                    qt.qpa.xcb: could not connect to display 
                                    qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
                                    This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
                                    ``
                                    JonBJ Online
                                    JonBJ Online
                                    JonB
                                    wrote on last edited by
                                    #150

                                    @phil-lipp
                                    https://forum.qt.io/post/763171 was just asked.

                                    1 Reply Last reply
                                    0
                                    • M Offline
                                      M Offline
                                      MarsOnMart
                                      wrote on last edited by
                                      #151

                                      I had too problems with this file.
                                      It just depends from which shared file left you.
                                      first at all set in the console :

                                      export QT_DEBUG_PLUGINS=1

                                      This will show you in which part it fails, normally is in libqxcb.so,

                                      example:
                                      python main.py

                                      qt.core.plugin.factoryloader: checking directory path "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms" ...
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqwayland-generic.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqwayland-generic.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "wayland"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QWaylandIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("wayland")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqminimal.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqminimal.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "minimal"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QMinimalIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("minimal")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqeglfs.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqeglfs.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "eglfs"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QEglFSIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("eglfs")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqwayland-egl.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqwayland-egl.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "wayland-egl"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QWaylandEglPlatformIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("wayland-egl")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqoffscreen.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqoffscreen.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "offscreen"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QOffscreenIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("offscreen")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqlinuxfb.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqlinuxfb.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "linuxfb"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QLinuxFbIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("linuxfb")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqvnc.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqvnc.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "vnc"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QVncIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("vnc")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqvkkhrdisplay.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqvkkhrdisplay.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "vkkhrdisplay"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QVkKhrDisplayIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("vkkhrdisplay")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqminimalegl.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqminimalegl.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "minimalegl"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QMinimalEglIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("minimalegl")
                                      qt.core.plugin.factoryloader: looking at "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so"
                                      qt.core.plugin.loader: Found metadata in lib /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so, metadata=
                                      {
                                          "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
                                          "MetaData": {
                                              "Keys": [
                                                  "xcb"
                                              ]
                                          },
                                          "archlevel": 1,
                                          "className": "QXcbIntegrationPlugin",
                                          "debug": false,
                                          "version": 394496
                                      }
                                      
                                      
                                      qt.core.plugin.factoryloader: Got keys from plugin meta data QList("xcb")
                                      qt.core.plugin.factoryloader: checking directory path "/usr/bin/platforms" ...
                                      qt.core.library: "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so" cannot load: Cannot load library /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so: (libxcb-cursor.so.0: cannot open shared object file: No such file or directory)
                                      qt.core.plugin.loader: QLibraryPrivate::loadPlugin failed on "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so" : "Cannot load library /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so: (libxcb-cursor.so.0: cannot open shared object file: No such file or directory)"
                                      qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
                                      This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
                                      
                                      Available platform plugins are: wayland, minimal, eglfs, wayland-egl, offscreen, linuxfb, vnc, vkkhrdisplay, minimalegl, xcb.
                                      
                                      zsh: IOT instruction  python main.py
                                      
                                      

                                      And this error occurs when some of the shared libraries are not found.
                                      In my case was the :
                                      "/usr/bin/platforms" ...
                                      qt.core.library: "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so" cannot load: Cannot load library /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so:

                                      == =>(libxcb-cursor.so.0: cannot open shared object file: No such file or directory) <===

                                      qt.core.plugin.loader: QLibraryPrivate::loadPlugin failed on "/home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so" : "Cannot load library /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so: (libxcb-cursor.so.0: cannot open shared object file: No such file or directory)"
                                      .
                                      This is the shared library that lefts , it could that does not be the only one , so for see better which shared libraries are and which not use the next command :

                                      ldd : /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so

                                      This must show you the next thing :

                                      ::
                                      ldd: ./:: No such file or directory
                                      /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/libqxcb.so:
                                              linux-vdso.so.1 (0x00007fff8b5b6000)
                                              libQt6XcbQpa.so.6 => /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/../../lib/libQt6XcbQpa.so.6 (0x00007febd8bec000)
                                              libxkbcommon-x11.so.0 => /lib/x86_64-linux-gnu/libxkbcommon-x11.so.0 (0x00007febd8bc3000)
                                              libxkbcommon.so.0 => /lib/x86_64-linux-gnu/libxkbcommon.so.0 (0x00007febd8b7d000)
                                              libxcb-cursor.so.0 => not found
                                              libxcb-icccm.so.4 => /lib/x86_64-linux-gnu/libxcb-icccm.so.4 (0x00007febd8b76000)
                                              libxcb-image.so.0 => /lib/x86_64-linux-gnu/libxcb-image.so.0 (0x00007febd8b6e000)
                                              libxcb-keysyms.so.1 => /lib/x86_64-linux-gnu/libxcb-keysyms.so.1 (0x00007febd8800000)
                                              libxcb-randr.so.0 => /lib/x86_64-linux-gnu/libxcb-randr.so.0 (0x00007febd8b5d000)
                                              libxcb-render-util.so.0 => /lib/x86_64-linux-gnu/libxcb-render-util.so.0 (0x00007febd8400000)
                                              libxcb-shm.so.0 => /lib/x86_64-linux-gnu/libxcb-shm.so.0 (0x00007febd8b58000)
                                              libxcb-sync.so.1 => /lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007febd8b50000)
                                              libxcb-xfixes.so.0 => /lib/x86_64-linux-gnu/libxcb-xfixes.so.0 (0x00007febd8b45000)
                                              libxcb-render.so.0 => /lib/x86_64-linux-gnu/libxcb-render.so.0 (0x00007febd8b37000)
                                              libxcb-shape.so.0 => /lib/x86_64-linux-gnu/libxcb-shape.so.0 (0x00007febd8b32000)
                                              libxcb-xkb.so.1 => /lib/x86_64-linux-gnu/libxcb-xkb.so.1 (0x00007febd8b15000)
                                              libxcb.so.1 => /lib/x86_64-linux-gnu/libxcb.so.1 (0x00007febd8aeb000)
                                              libQt6OpenGL.so.6 => /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/../../lib/libQt6OpenGL.so.6 (0x00007febd8a4a000)
                                              libQt6Gui.so.6 => /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/../../lib/libQt6Gui.so.6 (0x00007febd7a00000)
                                              libGL.so.1 => /lib/x86_64-linux-gnu/libGL.so.1 (0x00007febd8779000)
                                              libQt6Core.so.6 => /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/../../lib/libQt6Core.so.6 (0x00007febd7200000)
                                              libX11-xcb.so.1 => /lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007febd8a43000)
                                              libX11.so.6 => /lib/x86_64-linux-gnu/libX11.so.6 (0x00007febd8637000)
                                              libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007febd8a3c000)
                                              libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007febd8a37000)
                                              libstdc++.so.6 => /lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007febd6e00000)
                                              libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007febd7921000)
                                              libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007febd8a17000)
                                              libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007febd701f000)
                                              libxcb-cursor.so.0 => not found
                                              libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007febd6cbd000)
                                              libgthread-2.0.so.0 => /lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007febd8a10000)
                                              libxcb-util.so.1 => /lib/x86_64-linux-gnu/libxcb-util.so.1 (0x00007febd8a08000)
                                              libXau.so.6 => /lib/x86_64-linux-gnu/libXau.so.6 (0x00007febd8a03000)
                                              libXdmcp.so.6 => /lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007febd6a00000)
                                              libEGL.so.1 => /lib/x86_64-linux-gnu/libEGL.so.1 (0x00007febd861f000)
                                              libfontconfig.so.1 => /lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007febd78d6000)
                                              libQt6DBus.so.6 => /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/../../lib/libQt6DBus.so.6 (0x00007febd693b000)
                                              libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007febd83e1000)
                                              libfreetype.so.6 => /lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007febd6870000)
                                              libGLdispatch.so.0 => /lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007febd67b7000)
                                              libGLX.so.0 => /lib/x86_64-linux-gnu/libGLX.so.0 (0x00007febd78a2000)
                                              libicui18n.so.56 => /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/../../lib/libicui18n.so.56 (0x00007febd6200000)
                                              libicuuc.so.56 => /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/../../lib/libicuuc.so.56 (0x00007febd5e00000)
                                              libicudata.so.56 => /home/user/.local/lib/python3.11/site-packages/PySide6/Qt/plugins/platforms/../../lib/libicudata.so.56 (0x00007febd4400000)
                                              librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007febd8616000)
                                              /lib64/ld-linux-x86-64.so.2 (0x00007febd8ca7000)
                                              libpcre2-8.so.0 => /lib/x86_64-linux-gnu/libpcre2-8.so.0 (0x00007febd6c23000)
                                              libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007febd83cb000)
                                              libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007febd678c000)
                                              libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007febd6736000)
                                              libpng16.so.16 => /lib/x86_64-linux-gnu/libpng16.so.16 (0x00007febd6700000)
                                              libbrotlidec.so.1 => /lib/x86_64-linux-gnu/libbrotlidec.so.1 (0x00007febd8607000)
                                              libmd.so.0 => /lib/x86_64-linux-gnu/libmd.so.0 (0x00007febd7895000)
                                              libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007febd4331000)
                                              libbrotlicommon.so.1 => /lib/x86_64-linux-gnu/libbrotlicommon.so.1 (0x00007febd66dd000)
                                              libcap.so.2 => /lib/x86_64-linux-gnu/libcap.so.2 (0x00007febd6c17000)
                                              libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007febd41ea000)
                                              liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007febd66ae000)
                                              libzstd.so.1 => /lib/x86_64-linux-gnu/libzstd.so.1 (0x00007febd412e000)
                                              liblz4.so.1 => /lib/x86_64-linux-gnu/liblz4.so.1 (0x00007febd61da000)
                                              libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007febd4106000)
                                      

                                      As you can see the shared library which is not , appears like not found

                                          libxcb-cursor.so.0 => not found
                                      

                                      Just thus easier to fix it , is using :

                                      sudo apt install libxcb-cursor0

                                      In your case could be another like: libxcb-randr0

                                      1 Reply Last reply
                                      1
                                      • T twar

                                        Hello.
                                        After last qt5 update I'm getting this message:

                                        ~ $ qtcreator
                                        qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
                                        This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
                                        
                                        Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, xcb.
                                        
                                        Aborted (core dumped)
                                        

                                        Here is strace log https://pastebin.com/1GfBFmUH

                                        Linux disto is manjaro which is based on archlinux. Any idea what is going on?

                                        Thank you and best regards.

                                        I Offline
                                        I Offline
                                        IuriiV
                                        wrote on last edited by
                                        #152

                                        @twar Hi, solved by sudo apt-get install libxcb*

                                        F O 2 Replies Last reply
                                        2
                                        • I IuriiV

                                          @twar Hi, solved by sudo apt-get install libxcb*

                                          F Offline
                                          F Offline
                                          fokhagyma
                                          wrote on last edited by
                                          #153

                                          @IuriiV Thank you, it solved for me too.

                                          1 Reply Last reply
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