“A specified communication resources(port) is already in use” when attaching the debugger

Question

I have just upgrade my windows phone 8 to windows phone 8.1. When I connect my phone to pc and run my project it gives me

Answer 1

I had exactly the same problem. In my case installing Update 4 RTM for VS 2012 helped and I could once again debug my apps (previously, I had Update 4 RC installed). However, the error still appears if I open VS 2012 and VS 2013 side by side - if only one of them is open at the time then the error won't pop up.

Updating to Vs2012 Update 4 RTM, then we can debug on Phone