Unfortunately, only Ubuntu LTS distributions and RHEL/CentOS distributions are supported. That said, that error means that there was an error loading the Qt user interface toolkit.  Most likely there is a missing or wrong version of a shared library.  Try running "ldd /usr/lib/ucsf-chimerax/lib/python3.9/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so". (On CentOS that would be /usr/libexec/UCSF-ChimeraX instead of /usr/lib/ucsf-chimerax.)  I would expect there would some lines with "not found" in them.  Then you'll need to figure out how to get the missing shared libraries. Alternatively, you could upgrade to Debian 11.  A user was able to get ChimeraX installed there by using "dpkg  -i --ignore-depends=libllvm10 ucsf-chimerax...deb" using the Ubuntu 20.04 version of ChimeraX.  They also had to install the other dependencies separately.     -- Greg On 10/20/2021 10:43 AM, Stephen P. Molnar via ChimeraX-users wrote:

I am attempting the installation of ChimeraC-1.2.5(chimerax-1.2.5-rc-2021.05.24) on my up to date Debian v-1064 bit platform. I  open the tar.gz package without any difficulties, but when I attempt to execute ChmieraX i get the following:

comp@AbNormal:~/Apps/chimerax-1.2.5-rc-2021.05.24/bin$ ./ChimeraX 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, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.

Fatal Python error: Aborted

Current thread 0x00007fcb3dafd740 (most recent call first):   File "/home/comp/Apps/chimerax-1.2.5-rc-2021.05.24/lib/python3.8/site-packages/chimerax/ui/gui.py", line 157 in __init__   File "/home/comp/Apps/chimerax-1.2.5-rc-2021.05.24/lib/python3.8/site-packages/ChimeraX_main.py", line 577 in init   File "/home/comp/Apps/chimerax-1.2.5-rc-2021.05.24/lib/python3.8/site-packages/ChimeraX_main.py", line 1015 in <module>   File "/home/comp/Apps/chimerax-1.2.5-rc-2021.05.24/lib/python3.8/runpy.py", line 87 in _run_code   File "/home/comp/Apps/chimerax-1.2.5-rc-2021.05.24/lib/python3.8/runpy.py", line 194 in _run_module_as_main Aborted comp@AbNormal:~/Apps/chimerax-1.2.5-rc-2021.05.24/bin$

xcb is installed, but the Debian v-10 default version of python is 3.7. Is this the problem?

Is there a solution? Reinstalling did not fix the problem.

Thanks in advance.