I’m using the Roon app on a windows pc. On starting the app today and starting playback it suddenly stopped with the message that the album had been deleted. On further investigation all my Qobuz albums have disappeared. Have tried logging out of Qobuz and back in and restoring from backup but no joy. All the favourite albums are still listed under my favourites on Qobuz itself. Tidal is OK.
Having same problem here. 
Same problem here (as of today). Albums reappeared after restore from backup. However, they disappeared immediately after opening first album. Now all backups have disappeared too.
I run into that issue yesterday as well. Luckily I found an older backup that I still could access.
Still trying to understand where this was coming from.
@support - I want to make a support request for this, but how do I document something, if I do not see it anymore.
In any case, I am back as it should be (for now) , Library is back OK after the Qobuz synchronisation problem and new backups have been made.
I am taking screenshots from my Backup page, in order to have something if this would happen again.
Dirk
We are looking into this and will keep everyone updated here: