Several folks have run into a problem after uninstalling VS 2010 Beta 2 and installing VS 2010 RC.  When VS 2010 runs, you get an error message like the following.

Team Foundation Error

Could not load type

‘Microsoft.TeamFoundation.Client.TeamFoundationServerBase’ from assembly ‘Microsoft.TeamFoundationClient, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’.

The problem is that the TFS Power Tools for 2010 Beta 2 are installed.  Between Beta 2 and RC we made changes to the 2010 client API, so the Beta 2 power tools release will not work.  We do not currently have a release of the power tools for the RC (we are working on a power tools release for 2010 RTM).

The fix here is to uinstall the TFS Power Tools for 2010 Beta 2.  If after uninstalling it you still get the message, some folks have reported that in order to get rid of it they had to install the power tools again and then uninstall it.