"The type or namespace could not be found" error while building a project

Question

I am getting this error while trying to build a solution:

Error CS0246
The type or namespace name 'ClassName' could not be found (are you missing a using directive or an assembly reference?)

The error and the red lines disappear when I open the error list and click on it. I can see the missing dll file is recognized by that class and it is also listed in the references.

I searched many questions here but none of them worked for me. Here is a list of things I tried so far that might help to understand the problem.

• I've got the project from TFS and have been never able to build so far. I think the project is not correctly checked in.
• I choose 'build only' in the Error list section, after that the errors did not disappear.
• All project versions are .Net 4.6, none of them is Client Profile like other in questions here.
• I tried to clean, to rebuild, deleting references and adding them again, but none of them worked.

Answer 1

I have changed build output to Diagnostic then inspected errors.

I have found this line and changed all projects target version from 4.6 to 4.6.2 and it worked.

Dll could not be resolved because it was built against the ".NETFramework,Version=v4.6.2" framework. This is a higher version than the currently targeted framework ".NETFramework,Version=v4.6".