System.BadImageFormatException caused by NUnit project

Question

Good day everyone. I have been having the same problem all day at work and am struggling to find any new paths to go down.

I am getting the following error when my

Answer 1

Check the target framework version of your assembly are same as nUnit test runner supports. See runFile.exe.config for list of supported runtimes.

Also if you have megrated from FW 3 to FW 4, they has different runtime (CLR is different).