Hi Mun, not enough I'm afraid as it looks like a minidump rather than a full dump. In any case I doubt it will be useful, I did a bit of research and I'm not sure analyzing it will give us any clue of what's going on. I believe the very best thing we could do is experiment, but it takes time especially as we don't have access to that code and cannot reproduce the problem. In any case one somewhat simple thing you could do is compile nunit for .net 4.0 and try to run your tests with it, after you compile them and your production code for .net 4.0 too. Since these kind of exceptions might be related to the CLR itself (although quite unlikely) it might be something which in CLR 4 went away. To compile NUnit for 4.0 pull the code from launchpad with a bazaar client and just run build net-4.0 in the root folder. Simone On Fri, Oct 12, 2012 at 11:52 AM, Mun Wai Chan