Upgrading to TFS 2010? You need this HOTFIX.

 

If you are in the process of upgrading to TFS 2010 from any earlier version, please be aware of this HOTFIX:

support.microsoft.com/kb/2135068

It is a very specific HOTFIX in that it needs to be applied *after* your upgrade to 2010 is complete (i.e., you’ve uninstalled  2005\08 and installed the 2010 bits), but *before* you start the configuration of TFS 2010. If you don’t do it here, it cannot be done after 2010 has been configured. Your only recourse then is to redo the upgrade using backups of the TFS 2005\08 databases, or to contact us here in support and we will help. That call will be free of charge, of course. Even if a credit card number is requested in order to open the case, the charge will be refunded.

HTH,
-Trev