Cannot obtain value of local or argument as it is not available at this instruction pointer, possibly because it has been optimized away

Question

Visual Studio 2010 kills (there is no other word) data in one of the arguments of the function in the unsafe block. What could cause this error? The following message shows

Answer 1

In my case, I was working on a web api project and although the project was set correctly to full debug, I was still seeing this error every time I attached to the IIS process I was trying to debug. Then I realized the publish profile was set to use the Release configuration. So one more place to check is your publish profile if you're using the 'Publish' feature of your dotnet web api project.