Visual Studio: The project file ” has been renamed or is not longer in the solution
Problem:
You have removed a project outside of Visual Studio IDE, but that project was referenced by a Web site(s) included in same solution.
After the VS loading you are removing the absent project from a Solution Explorer.
Then you are trying to build your solution and got the error message shown at the picture:
“The project file ” has been renamed or is not longer in the solution”
Yes, it is true and you VS here is fully correct 
But it does not solve the problem.
Solution:
Please look at the Property Pages of your web site(s) and you will see the the following - one (because we are talking about only one removed project) of the items in References tab will be marked as unavailable.
Remove it (click “Remove”), click “OK” and try to build your solution again.
Good luck !