Comment 1 for bug 1920255

this also happens with mtools

$ mtools --help
Sorry, command-not-found has crashed! Please file a bug report at:
https://bugs.launchpad.net/command-not-found/+filebug
Please include the following information with the report:

command-not-found version: 0.3
Python version: 3.9.2 final 0
Distributor ID: Ubuntu
Description: Ubuntu Hirsute Hippo (development branch)
Release: 21.04
Codename: hirsute
Exception information:

database disk image is malformed
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/CommandNotFound/util.py", line 23, in crash_guard
    callback()
  File "/usr/lib/command-not-found", line 95, in main
    if not cnf.advise(args[0], options.ignore_installed) and not options.no_failure_msg:
  File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 344, in advise
    packages = self.get_packages(command)
  File "/usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py", line 97, in get_packages
    return self.db.lookup(command)
  File "/usr/lib/python3/dist-packages/CommandNotFound/db/db.py", line 19, in lookup
    for row in self.con.execute(
sqlite3.DatabaseError: database disk image is malformed