looks like something under /usr/lib/vst/, most probably carla.vst, is interrupting prematurely the VST plugin scan process (qtractor_vst_scan).
don't know if it applies but maybe carla.vst still has some links to old Qt4 widget styles which cannot co-exist onto a Qt5 process address space (or/and vice-versa)... once before it would suffice to remove the styles symlink under carla.vst sub-directory, in your case:
sudo rm -vf /usr/lib/vst/carla.vst/styles
that will do, hopefully, and won't cripple carla-vst in any major way, hopefully you will only loose some skinning or style themeing capabilities to carla-vst, but that's just sugary eye-candy, nothing fundamentally critical ;)
in case you want to revert the hack, without reinstalling Carla altogether, that is:
looks like something under
/usr/lib/vst/, most probablycarla.vst, is interrupting prematurely the VST plugin scan process (qtractor_vst_scan).don't know if it applies but maybe carla.vst still has some links to old Qt4 widget styles which cannot co-exist onto a Qt5 process address space (or/and vice-versa)... once before it would suffice to remove the
stylessymlink undercarla.vstsub-directory, in your case:sudo rm -vf /usr/lib/vst/carla.vst/stylesthat will do, hopefully, and won't cripple carla-vst in any major way, hopefully you will only loose some skinning or style themeing capabilities to carla-vst, but that's just sugary eye-candy, nothing fundamentally critical ;)
in case you want to revert the hack, without reinstalling Carla altogether, that is:
sudo ln -svf /usr/lib/carla/styles /usr/lib/vst/carla.vst/styleshth.
cheers