Today I checked in the code to TFS, I got the following error. My developers also had the same issue.
This error didn’t mean anything to me. Where is CheckForComments.cs? Microsoft should provide more meaningful information.
Internal error in Changeset Comments Policy. Error loading the Changeset Comments Policy policy (The policy assembly 'Microsoft.TeamFoundation.PowerTools.CheckinPolicies.ChangesetComments, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' is not registered.). Installation instructions: To install this policy, follow the instructions in CheckForComments.cs.
After installing TFS powerful tools 2011, this error was gone.