Hi Ralf,
At the moment, it isn't possible to get any history of test results using NCrunch. A new test run will overwrite any existing state held by NCrunch for the test.
The problem you're experiencing is very common though. As we delve more and more into the realms of asynchronous programming, we tend to collect more and more tests that annoyingly fail on occasion.
Being able to pull up detailed history (and perhaps an in-depth analysis) for a test would be really useful in figuring out its pass/fail pattern. It would take a bit of development to implement this though. Would you like to
request it as a feature?.