All files in the sync folder '' folder were deleted on the server

I’ve received this message twice today on two different accounts:

All files in the sync folder ‘foobar’ folder were deleted on the server.
These deletes will be synchronized to your local sync folder, making such files unavailable unless you have a right to restore.
If you decide to keep the files, they will be re-synced with the server if you have rights to do so.
If you decide to delete the files, they will be unavailable to you, unless you are the owner.

However, no files were touched neither locally nor on the server.

Anyone got any idea what this is?

I’m on Ubuntu 16.10 using latest Nextcloud client.

Check the clock on your server and client. It is used to determine what file is newer and if the clock is significantly off you can get problems like these.

This is a hosted nextcloud, so I can’t check the server clock. Anyways, is the server clock not displayed somewhere in Nextcloud?

I had something similar last week where my personal files were removed from the server, while other users weren’t. The server is synced over NTP, as are my 2 clients. Since I had all files still on the clients I was able to restore it. But was surprised the clients (both) stated all files were removed from the server.

now I had another user call in because it displayed the message there, aswell. Same, that no files were remoed on the server. This is getting scary.

Now I had this message again on my own nextcloud client. I can’t see anything in the server logs. I have no idea how to troubleshoot this?