Windows Server stops syncing


I have a Windows server that is using Client 6.1.3 and it stops syncing to the Seafile Server 6.1.2 Ubuntu 16.04, I have had this happen a few times with this PC and I have to totally remove the repo at the Seafile server, remove the client (and settings) from the Windows Server and start all over again and wait another 9 days for it to sync :-/

Seafile log on the client has thousands of these lines at the pint it fails:-

[12/18/17 17:38:02] sync-mgr.c(1959): No master branch found for repo Company Shared(8ea09b6b).

Right clicking the library on the client only gives the following options:-

Sync this library
View on cloud
open cloud file browser
show details

So lots of the normal options have vanished.

Any ideas how to fire this back into syncing without starting over ??