Movies disappearing after library update finishes

How to find the discrepancy between number of files on disk and the number of movies in the Plex movie library

And / or post log files:

  1. activate debug logging (not ‘verbose’!)
  2. quit Plex Server
  3. wait 1 minute
  4. start Plex Server
  5. wait 2 minutes
  6. update your library
  7. wait 3 minutes
  8. fetch log files and attach them here