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 had this issue (and its an issue I have seen in other places not just VS).

It's caused by Dropbox (in my case). After editing some code and hitting run, sometimes dropbox immediately locks the file (so it can process it).

Solution 1. Just hit run again

Solution 2. Pause dropbox. (not good if your using dropbox as your cloud backup)

Solution 3. Remove the build folder from dropboxes sync list.