In visual studio 2010 under the test settings < data and diagnostics tab < configuration for Code Coverage you can choose whether to instrument assemblies in place when you select which assemblies you wish to apply code coverage analysis to.
By default instrument assemblies in place is checked, however when it is checked anytime I run my unit tests I will be told there is no code coverage xml file being generated. If I choose to not instrument assemblies in place it works fine.
What gives?