- download a database tool for SQLite (e.g. DB Browser for SQLite => https://sqlitebrowser.org/)
- stop your server/game and download your game.db
- save a backup of this unmodified game.db in case you messed it up
- open it in the db browser
- go to the table actor_position
- sort by column class and search for entries that start with /Game/Mods/…
- delete all rows of old mods
- save the game.db
- upload it to your server/copy into your game and start again
be aware: this will not remove all kind of data related to the removed entries. this is really only a quickfix if you can’t wait for a robust solution or a fix from funcom