Namespace not recognized (even though it is there)

Question

I am getting this error:

The type or namespace name \'AutoMapper\' could not be found (are you missing a using directive or an assembly reference?)

Answer 1

I faced similar problem of namespace/method not being found during execution although it was fine during compilation, and the reason for this appears to be that the assembly I was referencing was deployed to GAC and since then was changed, so when I referenced the assembly in Visual Studion it was using the most recent one, but during runtime the version fro GAC had been used.