I recently did an in-place upgrade of my Fedora 33 templates to Fedora 34 using the process described at qubes-os.org on Qubes 4.1. My Brave browser snap still worked after updating, restarting the VMs, etc. A few days later after doing some additional template updates, I can’t run my Brave snap. I have both snapd and qubes-snap-helper installed. This is the output I get from the terminal:
WARNING: cgroup v2 is not fully supported yet, proceeding with partial confinement cannot perform operation: mount --rbind /dev /tmp.snap.rootfs_bnPFo2//dev: No such file or directory
I tried removing the snap and re-installing according to the instructions for snap installs listed on qubes.os.org, but I get the same output. I get the same output with a different /tmp.snap folder name when trying to run ‘snap install chromium’ during the ‘Run configure hook’ part of the snap installation. The folder listed in the output is just an empty folder, and deleting that folder simply generates a new empty temporary folder when I try to run the snap again.
I am also sometimes getting startup errors on the VM in question like qrexec timeout errors.