Question : Global Catalog Not Working In Branch Office Locations After Introduction of One Server 2008 And Upgrading Domain

Some time ago, I set up a server in one of our branch office locations running Server 2008.  The rest of the domain is on Server 2003 with the home office holding the FSMO Roles.

Set up the server and went through the process of upgrading the domain to be able have the 2008 server join the domain.  No problems there, however, none of the branch office domain controllers seem to be working as local Global Catalog Servers anymore even though they are set to be GC.  Users in the branch offices can only authenticate if they are able to access the main Domain Controller in the home office.  We currently have a situation where their service is down and they cannot contact the home office, therefore cannot access any of their local resources.

Not sure what's happening here.  It worked when everything was on 2003.

Answer : Global Catalog Not Working In Branch Office Locations After Introduction of One Server 2008 And Upgrading Domain

I would suggest:
Remove the GC role from the server/s that are not functioning.
Reboot the server & force replication.
After you are sure that replication has completed, re-add the role.
Again, force replication, then run DCdiag in verbose mode & check for errors.