title: Why can't I attach TFS to a Project Collection that was restored to SQL Server (I think) correctly?
body: <p>We tried moving a TFS Project Collection from one TFS 2010 server to another.</p>
  
  <ol>
  <li>Detached the collection in TFS Console on source server</li>
  <li>Backed up the collection, Tfs_DefaultCollection, in SQL Server 2008 Standard Edition</li>
  <li>DBA restored the Collection to a new database, Tfs_MyCollection, to the SQL Server 2008 Enterprise, R2, instance used by the target TFS Server.</li>
  <li>TFS Administrator attempted to attach to the target server.</li>
  </ol>
  
  <p>TFS adminisitrator received the following error message.</p>
  
  <blockquote>
    <p>TF254078: No attachable databases were found on the following instance
    of SQL Server: MyServerName. Verify that both the name of the server
    and the name of the instance are correct and that the database was
    properly detached using the detach command in the Team Foundation
    Administration Console.</p>
  </blockquote>
  
  <p>I assmumed we did not need to prepare the database instance in the target server since it already contained a TFS Project Collection.
  I assumed that going up in a SQL Server edition was acceptable.</p>
  
  <p>Are my assumptions valid?
  What could be the cause of not being able to attach to the new TFS Server?</p>
  
  <p>btw, I created this post on ServerFault originally <a href="https://serverfault.com/questions/392725/why-cant-i-attach-tfs-to-a-project-collection-that-was-restored-to-sql-server-c">Mirror in Serverfault</a>, but it generated very little interest there.</p>