(Exception from HRESULT: 0x80070020) asp.net Visual studio

I get this error every time I debug in Visual studio with web applications. The first time I debug it will open and run normal, but then it just stops. AM I missing something? this happens even when I have a black page.

Isn't that error straight forward. The assembly file for WebOne is already loaded and being used by another process. You can check where it's open and close it. Close and re-run VS again.