- Restore a database file from before the move.
https://support.plex.tv/articles/202485658-restore-a-database-backed-up-via-scheduled-tasks/ - Shut down Plex server
- Make sure the movies are stored under the same folder names as they were on the old hard drive.
- Change the drive letter of the new drive to the drive letter of the old drive.
https://www.lifewire.com/how-to-change-a-drive-letter-2626069 - give the old drive a different drive letter
When you start plex server, it won’t notice anything has changed, since it still can find the movies under the old drive letter.
If you want to move content to other locations, without chaning anything about its metadata, edit the Plex database directly: [HowTo] Plex database modification - Moving media the right/wrong way
