VS 2017 Metadata file '.dll could not be found

Question

I know there is another question with exact the same problem, but I went trough all those answers, and none helped me. :( (This was the question.)

I just created a new A

Answer 1

I had this issue with a solution containing multiple projects.

It came from duplicating a .csproj and adding the copy to the solution. A .csproj file contains a element. I set the GUID of the copied project to a new one.

Update: Which GUID you use doesn't matter, it just needs to be different from the other project's GUID. You can create a new GUID from within Visual Studio: Tools -> Create GUID and copy the part between the curly brackets, i.e. {...}. Use that as the new value for the element.

I also performed the following steps (not neccessarily neccessary, but they don't hurt):

1. Close the solution
2. Delete bin folder
3. Delete all obj folders
4. Open solution and build