I am outraged that the community let this "payable" app fail without warning.
I too have just realized that owncloud isn't working right after I've converted the damn kvm machine to lxc and made everything work as it should (openvpn, nfs mounts, lvm mounts,..).
I've spent a few hours doing the conversion and then went ahead checking if everything works.
Well everything works except for the Owncloud app.
Reading about how it auto-updated to oblivion, I've even tried to revive the damn thing. After disabling an extra app, I've set "maintenance" to off.. guess what? All my users are gone. Only admin remains.

What?????!!!??!?!?!?

Tell me... who was the boss that let this happen? This is not the way upgrades were supposed to go.
I mean.. you didn't auto-replace zarafa with kopano. I guess there's a good reason not to do that.

What do I do now? I have all the files on the filesystem, so I'm ok. I'll just take the files and documents to a safer place.