The type or namespace does not exist

Question

I am unable to build my project because it thinks a namespace doesn't exist.

There is no red line in the editor, and I can navigate to the types in that namespace by hitting F12 on the type.

Why is this incorrect error msg coming through?

I have tried cleaning/building, and rebuilding the project, as well as restarting VS.

Answer 1

I don't know if this helps: try to unload the project and load it again . Right cklick on the Project in Project Explorer and unload this. here example in German Context Menu

Answer 2

As Stefan said try unload and load the project.

It looks like the issue is happening in your testing project. Try to delete and re-add the corresponding references.