Visual Studio's Intellisense is faulty: CS0234 The type or namespace name <name> does not exist in the namespace <namespace>

Question

I'm working on a repository that I've had no problem with it until recently. None of my colleagues are having problems on their machines either, so I'm led to believe this is a problem with my Visual Studio.

I keep getting hundreds of errors, as follows:

Error CS0234 The type or namespace name <name> does not exist in the namespace <namespace> (are you missing an assembly reference?)

It's like all of the references are broke. But when I build there are no build errors. Just Intellisense errors.

Does anyone know what's going wrong?

Answer 1

The situation you encountered is a common issue that may meet.

This situation caused by some intellisense information stored in .vs folder.

Take a look of this:

Still forced to delete ".vs" folder to fix build errors or IntelliSense errors

After you delete/remove the .vs folder and restart the visual studio, the visual studio will regenerate a new .vs folder with the new intellisense information.

By the way, this behavior was not recorded in official documents.