Build error: “The process cannot access the file because it is being used by another process”

Question

I\'ve got a C# webforms app, that until today had been working just swimmingly.

Now today, all of a sudden, every time I try run the app, I get a file l

Answer 1

I use Visual Studio Code and I received this error because the dev server was running (I ran the dev server by pressing Ctrl + F5).

Thus, I just clicked on the stop sign to stop it and the error went away.