I am in the process of upgrading from dirsync to adconnect and got a failure in the middle of the upgrade. The error log mentions this error:
Exception Data (Raw): System.Exception: Unable to install the Synchronization Service. Please see the event log for additional details. ---> System.DirectoryServices.AccountManagement.NoMatchingPrincipalException: Group 'FIMSyncAdmins' was not found.
I do not see that group at all locally on the server (other FIM groups are local on that server apparently), and I do not see it listed in AD either. I do see MIISAdmins group, but not sure that is the same thing or not. I tried running AD Connect install again and it said to post a question to the MSDN forum.
Thanks!