How to rebuild Sysvol and Netlogon Folders
I ran into an interesting issues where at a customer site netlogon and sysvol folders had disappeared from both domain controllers they had and I had to fix it so that my Citrix Profile Manager GPO will apply correctly (Totally out of the scope for the VDI project). Anyhow what I ended up having to do was backup sysvol contents, setup FSMO role holder authorative for FRS replica and setup another DC as non-authorative recpient for FRS replica. Step by step details are provided in MS KB article below
http://support.microsoft.com/kb/315457
While reading up on it I also came across few interesting reading topics as well which are listed below
http://support.microsoft.com/kb/316790
http://support.microsoft.com/kb/947022
http://technet.microsoft.com/en-us/library/dd277429.aspx
http://technet.microsoft.com/en-us/library/cc758169%28WS.10%29.aspx