When you get the error: Error while trying to run project: ‘C:\…’

The debugger’s protocol is incompatible with the debuggee

Check you’re supportedRuntime tag in you’re App.config or Web.config

I ported a .NET 4.0 C# application back to .NET 3.5 and got that message, removing the startup tag:

    <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>

Solved the problem





  1. I had that line in an NUnit.config file, which had been necessary to add to get NUnit to work with .Net 4. Your solution worked perfectly to unit-test a .Net 2 project, thanks!


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