Comment 4 for bug 1910300

I have encountered this as well. Horizon is erroring out due to the os.cwd() command raising FileNotFound, which essentially means that the directory or path that the command was operating from is no longer available.

I began to wonder why this would happen as the current working directory shouldn't be removed (or changed to a tempdir that was cleaned up).

Checking logs for snapd, I can see it was refreshed. Indeed, I can force this error by reverting snapd to a previous revision, e.g.:

$ snap list --all snapd
Name Version Rev Tracking Publisher Notes
snapd 2.49 11115 latest/stable canonical✓ snapd,disabled
snapd 2.49.1 11408 latest/stable canonical✓ snapd

$ sudo snap revert snapd
2021-03-26T14:22:48-07:00 INFO Waiting for automatic snapd restart...
snapd reverted to 2.49

and voila, the horizon dashboard now fails :-( with the traceback in this path.

(p.s. revert back to the latest snapd with sudo snap revert --revision <foo> snapd - which will break horizon-uwsgi once again).

This actually may also be related to losing networking as well.