Hi,
I have been upagrding a SQL2000 to SQL2008 R2 and along the way on Rules Check it failed with the following error:
Rule "Security Group SID (Security Identifier)" failed.
One or more selected features for upgrade have failed the SID check. See the rules documentation at http://go.microsoft.com/fwlink/?LinkId=94001 for information on how to resolve.
I've searched online and couldn't find a solution that helps....