This application failed to start because no Qt platform plugin could be initialized

[jsulm]

@adsavi You mean you built Qt by yourself?

[adsavi]

@jsulm the online installer gave me an error several times so finally used the offline one.

[jsulm]

@adsavi Not sure what you mean. Did you now install Qt using offline installer and it works or does it not work?
qt-everywhere-src-5.15.1.tar.xz is not offline installer but Qt source code archive.

[adsavi]

@jsulm I started from that file, unzip it, configure, chose the open source option, and then sudo make and sudo make install. When I tried it gave me the error I posted here.

[jsulm]

@adsavi Then you should check config.log file to see whether printing support was enabled or not

[adsavi]

@jsulm said in This application failed to start because no Qt platform plugin could be initialized:

config.log

the config.log text is:

====

executing config test gypsy

• cd /Users/adrianosavi/qtlocation/config.tests/gypsy && /Users/adrianosavi/qtbase/bin/qmake -spec /Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtbase/mkspecs/macx-clang "CONFIG -= qt debug_and_release app_bundle lib_bundle" /Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtlocation/config.tests/gypsy
• cd /Users/adrianosavi/qtlocation/config.tests/gypsy && MAKEFLAGS= make

/Library/Developer/CommandLineTools/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -std=gnu++11 -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=10.13 -fno-exceptions -Wall -Wextra -fPIC -DQT_NO_LINKED_LIST -DQT_NO_JAVA_STYLE_ITERATORS -DQT_NO_LINKED_LIST -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -I/Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtlocation/config.tests/gypsy -I. -I/Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtbase/mkspecs/macx-clang -o .obj/main.o /Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtlocation/config.tests/gypsy/main.cpp
/Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtlocation/config.tests/gypsy/main.cpp:29:10: fatal error: 'gypsy/gypsy-satellite.h' file not found
#include <gypsy/gypsy-satellite.h>
^~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make[1]: *** [.obj/main.o] Error 1
test gypsy FAILED
executing config test winrt

• cd /Users/adrianosavi/qtlocation/config.tests/winrt && /Users/adrianosavi/qtbase/bin/qmake -spec /Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtbase/mkspecs/macx-clang "CONFIG -= qt debug_and_release app_bundle lib_bundle" /Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtlocation/config.tests/winrt
• cd /Users/adrianosavi/qtlocation/config.tests/winrt && MAKEFLAGS= make

/Library/Developer/CommandLineTools/usr/bin/clang++ -c -pipe -stdlib=libc++ -g -std=gnu++11 -arch x86_64 -isysroot /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk -mmacosx-version-min=10.13 -fno-exceptions -Wall -Wextra -fPIC -DQT_NO_LINKED_LIST -DQT_NO_JAVA_STYLE_ITERATORS -DQT_NO_LINKED_LIST -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -I/Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtlocation/config.tests/winrt -I. -I/Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtbase/mkspecs/macx-clang -o .obj/main.o /Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtlocation/config.tests/winrt/main.cpp
/Users/adrianosavi/Downloads/qt-everywhere-src-5.15.1/qtlocation/config.tests/winrt/main.cpp:30:10: fatal error: 'windows.system.h' file not found
#include <windows.system.h>
^~~~~~~~~~~~~~~~~~
1 error generated.
make[1]: *** [.obj/main.o] Error 1
test winrt FAILED

====

It seems the configuration failed.
But I was able to go on with the following steps.
What do you suggest to me?

[jsulm]

@adsavi said in This application failed to start because no Qt platform plugin could be initialized:

What do you suggest to me?

What I already suggested: check the config.log file to see whether PRINTING support was activated or not. The failed checks are related to QtLocation module and do not have anything to do with printing...

[adsavi]

@jsulm I installed QT again and now I did not have any problem with the installation and the installation log shows no problem.

There is not printing support issues but now the message I receive is this:

===========

QFactoryLoader::QFactoryLoader() checking directory path "/Users/adrianosavi/opt/anaconda3/plugins/platforms" ...
QFactoryLoader::QFactoryLoader() looking at "/Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib"
Found metadata in lib /Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib, metadata=
{
"IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
"MetaData": {
"Keys": [
"cocoa"
]
},
"className": "QCocoaIntegrationPlugin",
"debug": false,
"version": 329991
}

Got keys from plugin meta data ("cocoa")
QFactoryLoader::QFactoryLoader() looking at "/Users/adrianosavi/opt/anaconda3/plugins/platforms/libqminimal.dylib"
Found metadata in lib /Users/adrianosavi/opt/anaconda3/plugins/platforms/libqminimal.dylib, metadata=
{
"IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
"MetaData": {
"Keys": [
"minimal"
]
},
"className": "QMinimalIntegrationPlugin",
"debug": false,
"version": 329991
}

Got keys from plugin meta data ("minimal")
QFactoryLoader::QFactoryLoader() looking at "/Users/adrianosavi/opt/anaconda3/plugins/platforms/libqoffscreen.dylib"
Found metadata in lib /Users/adrianosavi/opt/anaconda3/plugins/platforms/libqoffscreen.dylib, metadata=
{
"IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3",
"MetaData": {
"Keys": [
"offscreen"
]
},
"className": "QOffscreenIntegrationPlugin",
"debug": false,
"version": 329991
}

Got keys from plugin meta data ("offscreen")
QFactoryLoader::QFactoryLoader() checking directory path "/Users/adrianosavi/opt/anaconda3/bin/platforms" ...
Cannot load library /Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib: (dlopen(/Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib, 133): Library not loaded: @rpath/libQt5PrintSupport.5.dylib
Referenced from: /Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib
Reason: image not found)
QLibraryPrivate::loadPlugin failed on "/Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib" : "Cannot load library /Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib: (dlopen(/Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib, 133): Library not loaded: @rpath/libQt5PrintSupport.5.dylib\n Referenced from: /Users/adrianosavi/opt/anaconda3/plugins/platforms/libqcocoa.dylib\n Reason: image not found)"
qt.qpa.plugin: Could not load the Qt platform plugin "cocoa" 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: cocoa, minimal, offscreen.

Abort trap: 6

=====

What is the next step you suggest?

[jsulm]

@adsavi It can't load libqcocoa.dylib because it seems to depend on libQt5PrintSupport.5.dylib which it can't find for some reason.
I don't know why this happens (not a Mac user).
What Qt version did you install and how?

[adsavi]

@jsulm the version is Qt version 5.15.1 - Just installed today.
I found I have this file: /Users/adrianosavi/opt/anaconda3/lib/libQt5.archive/libQt5PrintSupport.5.9.7.dylib but I do not know fi there is any connection.

[jsulm]

@adsavi said in This application failed to start because no Qt platform plugin could be initialized:

installed today

How? Using online installer? Does it have libQt5PrintSupport.*.dylib?
libQt5PrintSupport.5.9.7.dylib - this is a different version

[adsavi]

@jsulm installed with an online installer. In my computer, there are no other dylib files beginning with libQt5PrintSupport.

[jsulm]

@adsavi said in This application failed to start because no Qt platform plugin could be initialized:

there are no other dylib files beginning with libQt5PrintSupport

This is strange, it should be there.
Maybe somebody else knows, I'm not a Mac user.

[adsavi]

@jsulm is there any way to know to which module of Qt this library belongs so that I can use the maintenance tool to try to reinstall again?

[SGaist]

Hi,

There's something fishy here. It looks like your have installed Qt using conda. I suspect it came with PySide2. Is that the case ?
Now if you used the online installer, how are you running your application ?

[adsavi]

@SGaist yes I have installed Conda. I try uninstall it but no change. I run the application from visual studio code but if I run it from the terminal I got this message:

adrianosavi@ProOne Dashboard % python test.py
Traceback (most recent call last):
File "test.py", line 2, in <module>
from PySide2.QtWidgets import QApplication, QDialog, QLineEdit, QPushButton
ImportError: No module named PySide2.QtWidgets
adrianosavi@ProOne Dashboard % python test.py
Traceback (most recent call last):
File "test.py", line 2, in <module>
from PySide2 import QtWidgets #import QApplication, QDialog, QLineEdit, QPushButton
ImportError: No module named PySide2
adrianosavi@ProOne Dashboard % pip install PySide2
Requirement already satisfied: PySide2 in /Users/adrianosavi/opt/anaconda3/lib/python3.8/site-packages (5.15.1)
Requirement already satisfied: shiboken2==5.15.1 in /Users/adrianosavi/opt/anaconda3/lib/python3.8/site-packages (from PySide2) (5.15.1)

[SGaist]

Looks like you installed all your stuff in the base conda environment which is a bad idea.

I would recommend re-install conda cleanly and create a proper environment to install PySide2.