Why did I get a 'Mixed product and instrumentation usage' error ? How do I get rid of it?
This is because TrueTime and TrueCoverage instrumented code can't co-exist together. If your application was instrumented with either one of them and then was instrumented with the other one, you may get this error.
To avoid this error, you can just do a regular 'Rebuild all' (inside or outside the VS IDE) without our tools involved to clean any instrumented code from the current build of your application.
This is also mentioned in the TrueTime ReadMe file.