Though my unit tests runs just fine (I'm just using MS Test, so can't blame using 3rd party tools) I get the following error when trying to view Code Coverage:

Cannot find any coverage data (.coverage or .coveragexml) files. Check test run details for possible errors.
I did check "Code Coverage" in my test settings (Test->Edit Test Settings->Local).

Weird, it worked fine in VS 2008. (Though this is a whole new project)