Once you are ready to start you need to make sure that no one can access the existing TFS 2008 server while you do the migration.

1. You are ready to start
2. Send out an email notifying all users that TFS2008 will be turned off. 
   Follow Rules to better Networks
3. Make sure no-one can check in files by either:
   1. Running TFSQuiesce (recommended)
      or
   2. Turning off TFS Service
      1. Remote desktop into TFS 2008
      2. Start IIS
      3. Right click Team Foundation Server | Stop
      
      Figure: You need to stop anyone checking in files 
4. Confirm you can no longer get latest on the Northwind team project