We are currently using a Windows 2003 GCS in a Windows 2008 R2 Enterprise Domain for LDAP Queries on a critical application (I know. I know. Working with the Vendor to get that removed.). Making matters more difficult, it's a Hyper-V Windows 2003 GCS on a Windows 2008 Standard Host Machine. A while back, something corrupted on the Windows 2003 GCS of which required a roll-back in Hyper-V. A known issue with Hyper-V is that sometimes when you do that to a GCS, it corrupts the AD Database over time. Sure enough, that's exactly what happened. Ultimately, the only thing I could do to resolve that issue was to completely rebuild AD on the Windows 2003 GCS. I did have to force the DC Demotion as since the Windows 2003 GCS had a corrupted database, the other GCSs refused the updates that the Windows 2003 GCS tried to send before it got demoted. This meant that I had to remove it manually from AD, DNS and Sites and Services on the Forest Domain Controller. Rebuilding AD in the Windows 2003 GCS went very well but somehow the Windows 2003 GCS is not creating an automatic connection to our Windows 2008 R2 Enterprise Forest Domain Controller (FDC) and vice-versa. On both of those Servers, replication is automatically generated with all other available GCS but not with each other. However, it did before. Not a critical issue as replication does occur but it would be nice if all replication could automatically happen at the FDC. I double checked that the Windows 2003 GC is listed as a GC in Sites and Services and it is. I also ran the following command where I put in my domain in place of "testenv" from the FDC and the response showed that the Windows 2003 GC is very much recognized as a DC: "nltest /dclist:testenv.local". Again, AD is working just fine on the Windows 2003 GCS and replication is occurring automatically between the Windows 2003 GCS and all of the other GCs of which are Windows 2008 R2 Enterprise or Windows R2 Standard or Windows 2008 Standard, just not with the FDC and vice-versa. It's just weird. Please help.