The index is stored inside the .cache file under the _NCrunch_Solution directory.
You can try deleting this file to see if it makes any difference - although I would really like to know how it's getting messed up.
Can you share any details on how these tests are structured? Are they making use of inheritance or interesting arrangements?
I can probably reproduce+fix this problem very quickly if you're able to supply a code sample that demonstrates the problem. This could be as simple as just taking your test project, removing its references and all the code except for the test declarations causing problems, and packaging this with the .cache information intact. You're welcome to submit any code through the
contact form.
Thanks!
Remco