This page contains a, possibly growing, list of commonly encountered issues during installing or running PyPO. This list is structured somewhat in a Q&A format. If you encounter an issue which is not listed here, please open an issue in the issue tracker of the PyPO repository. When the issue is resolved, we will add it to this list for bookkeeping and future reference.

Qt Errors

Q: When trying to run the GUI or the unittests on Linux, I get the following error:

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: vkkhrdisplay, offscreen, minimal, vnc, wayland, eglfs, wayland-egl, xcb, linuxfb, minimalegl.

A: This is due to the xcb library missing certain dependencies. In most cases, this can be resolved by running:

sudo apt install libxcb-cursor-dev

A generally useful tip for dealing with these Qt related bugs, is to first enable debugging in Qt. From the command line:

export QT_DEBUG_PLUGINS=1

This enables debugging when plugins for Qt are loaded and will give a list of libraries it could not load. With this information, it is then relatively easy to figure out what libraries are missing and should be installed.