Qt platform plugin xcb could not load - Qt6

[ryan_rockhopper]

Hello all,

I am new to both Ubuntu/Linux and Qt and I am trying to create my first Qt project. I am choosing a C++ Widget project with all of the default settings, and when I build I expected it to open a blank window (like it does on my Windows machine), however I get the following error. From my googling, it seems a library isn't linked? I'm not sure if that is the problem or what but I really don't know how to solve this. Any help would be appreciated.

[SGaist]

Hi and welcome to devnet,

Any chance you are running your desktop environment on top of Wayland ?

If so, one thing you can do is to go in the Run part of the project panel and set the QT_QPA_PLATFORM environment variable to wayland and restart your application.

[Paul Colby]

Hi @ryan_rockhopper,

This comes up quite often - try searching these forums for "xcb".

That said, here's my go-to solution: @Paul-Colby said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

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

For modern Ubuntu's, I resolve this with:

sudo apt install libxcb-cursor0

Cheers.

[ryan_rockhopper]

@SGaist

Hi SGaist,

How would I tell if I'm running my desktop environment on top of Wayland? Is that a setting in Ubuntu or some program/plugin that needs to be installed? Something else?

Thanks,
Ryan

[JoeCFD]

@ryan_rockhopper
echo $XDG_SESSION_TYPE

[ryan_rockhopper]

@Paul-Colby said in Qt platform plugin xcb could not load - Qt6:

sudo apt install libxcb-cursor0

Thank you Paul-Colby, that totally fixed it. You're the man!