Snaps are missing. I'd like to reinstall, but I can't seem to remove them first in order to reinstall. How do I fix this?
$ chromium-browser
cannot locate base snap core18: No such file or directory
$ snap list
Name Version Rev Tracking Publisher Notes
chromium 87.0.4280.88 1421 latest/stable canonical✓ -
core 16-2.48 10444 latest/stable canonical✓ core
core18 20200929 1932 latest/stable canonical✓ base
gnome-3-26-1604 3.26.0.20200529 100 latest/stable/… canonical✓ -
gnome-3-28-1804 3.28.0-19-g98f9e67.98f9e67 145 latest/stable canonical✓ -
gnome-3-34-1804 0+git.3556cb3 60 latest/stable canonical✓ -
gnome-system-monitor 3.36.0-12-g35f88a56d7 148 latest/stable/… canonical✓ -
gtk-common-themes 0.1-50-gf7627e4 1514 latest/stable/… canonical✓ -
snap-store 3.38.0-55-geb45541 498 latest/stable/… canonical✓ -
$ sudo snap install core18
snap "core18" is already installed, see 'snap help refresh'
$ sudo snap remove core18
error: cannot remove "core18": snap "core18" is not removable: snap is being used by snaps
chromium, gnome-3-28-1804, gnome-3-34-1804, gnome-system-monitor and 2 more.
$ snap version
snap 2.48+20.04
snapd 2.48+20.04
series 16
ubuntu 20.04
kernel 5.4.0-56-generic