Fatal error probably: If one of local media file was changed, the the sync would fail, user can only choose redownloading the whole collection, the server will also need to reboot

[HaujetZhao]

For example, if a local media file, a picture, was edited after a sync, the following sync would fail. and the server will also breakdown, other users can't sync anymore.

The only fix is to manually reboot the server and let the user redownload his whole collection.