Library shows no content after server update

With exception of the path names, yes it’s the same procedures.

Before trying to rebuild, have you used the backup copies and confirmed they are also damaged ?

To make checking / trying easier, the “PlexData” share mechanism is available to you.

  1. Create a shared folder named PlexData anywhere you like it
  2. Attempt to start Plex (the magic occurs when PMS starts — scripting)
  3. Open File Station
  4. PlexData → Plex Media Server
  5. You are now looking at the actual installation (what’s normally hidden under the App Center “.qpkg” directory structure)
  6. You can use FileStation to perform renaming / downloading / etc as needed.

Ref: PlexData share for QNAP systems