I was cracking my head wondering why my Nunit tests stopped running out of a sudden and I started getting the incredibly helpful message “Test Not Run” from Resharper until I found out that this problem is very likely to happen when your
app.config or web.config contains errors!
usually a bad format due to bad tag closing or syntax.
if you’re running the full suite rather than individual tests you may get “Tests inconclusive” which is usually related to the same thing. In my case I had a unit test doing a bad write to app.config which was screwing everything up for everyone.
so fix your config file and everything should be back to normal.