Someone asked a similar question before, getting the following error when I run MSpec in Visual Studio 2010:
Could not load file or assembly 'Machine.Specifications.dll' or one of its dependencies. The system cannot find the file specified.
The solution in the other post was to download the .net4 specific version of MSpec. But, that's what I'm using, and it still doesn't work. I even re-downloaded the latest today, and built it with the build-4.0-release.cmd file. Replaced my reference, and still had the same problem.
The strange thing is that the first time I run MSpec, it works just fine. It's only when I try to re-run it that I get this error.
The tests still run just fine in the ReSharper test-runner. So, it's still usable. But, the ReSharper test-runner doesn't generate the Report.html file. That's really the only reason I want to get it to work. Is there a way to get ReSharper to generate the Report.html file instead? That would also solve the problem.