Ok, this has now happened to me four times over the last couple of weeks, the fourth was just now and I was 100% clear what I had been doing and what I did to set this off.
I have one library of approximately 48,000 audio titles. There are three playlists; ALL Playlist, MAIN Playlist, OLDIES Playlist. ALL has everything, MAIN has everything from approximately 1980 to present, and OLDIES has everything from 50's to early 80's. There are approximately 20k entries in each of MAIN and OLDIES. I move things between playlists to organize which stream should play them. I never delete native files, which are all FLAC from 44k to 192k and 16 or 24 bit depth.
In each of the four cases, I've had all of one specific playlist name removed from the entire database, causing me major amounts of time to reconstruct. Yes, I do backups and that has helped, but it's still easy to chalk up hours of work between daily (or more often) backups.
Just a few minutes ago, I had selected a single entry in the Oldies Playing Now list, to remove that entry from the OLDIES category. There was a pause, and EVERY Playlist field record had OLDIES Playlist removed in the entire database.
The Playlist Field would typically look something like this:
ALL Playlist;MAIN Playlist;OLDIES Playlist for an entry that should appear in three playlists, or ALL Playlist;MAIN Playlist for an entry that would appear in the MAIN playlist. ALL Playlist is never played, it's just a list for browsing and placing entries.
I usually have each Playlist locked, but at the time this happened, OLDIES Playlist was unlocked because I had reordered the numbering a few minutes prior. I don't know if being locked would have prevented this from happening or not.
The library file contents are all on two local hard drives, across four directory hierarchies. There never seems to be issues with the ALL Playlist and the total library contents, only the derived Playlists. But when this happens the behavior remains the same. Some presumably innocuous single removal wipes out a whole playlist.
In this case I had ALL Playlist open in a window, and the Playing Now copy of OLDIES Playlist in another window. It was in that window where I unchecked the Playlist entry for the OLDIES Playlist that wiped out the entire list.
PLEASE tell me this is rare but known and a fix is forthcoming, not that I'm the only one experiencing it.
I have been able to add the OLDIES Playing Now List to add back all the OLDIES Playlist selections that it knows about, but it was several hours behind today's changes.
--Bill