This removes the previews from the old preview location that was used before Nextcloud 11. That has some issues. Note that the gallery shipped with Nextcloud 11 did not yet use this location. So you might want to run it again with Nextcloud 12.
preview:generate-all [user-id]
Loop over all files and try to generate previews for them. If user-id is supplied just loop over the files for that user.
preview:pre-generate
Do the actual pregeneration. This means only for new or modified files (since the app was enabled or the last pregeneration was done).
I tried it, but then I see the encryption problem.
But its curious, why isn’t there occ command “preview”? I’ve read about it in some other threads, but in my nextcloud the error message appears.