There is an issue where 2005/2008 clients connecting to a TFS 2010 RC server, with team projects created by RC versions of MSF Agile / CMMI process templates will encounter an error when resolving bugs. But there is a work around!
First, the error. If, when in the above situation, you attempt to resolve a bug as “Fixed” (the default resolution), you will get the following error when saving the bug:
TF20012 : Filed ‘Resolved Reason’ cannot be empty
The workaround is to select a Reason other than the default “Fixed”, then switch it back to “Fixed” again. Resolved Reason should then be updated, and you should be able to save the bug.
The problem will be resolved with the RTM versions of the MSF Agile/CMMI process templates.