Unable To Launch Web Server

Question

I have asp.net web application project in visual studio 2012. When I want to start it, I have the following error:

Unable to launch the IIS Express Web server: Port"4012" is in use

This problem came from nothing.How can I resolve it ?

Answer 1

I was having similar problem in visual studio 2012:

ERROR: " Unable to launch IIS Express web server.

Failed to register URL http://localhost:1030/ for site "MySite" application "/". Error Description: The process cannot use file because it is being used by another process. (0x85968574) "

REASON : Actually this port numbers are dynamically generated at runtime. It dosent guranteed to be available. If it is acquires by some other process project wont run. So we need to try at another port.

SOLUTION : There are various solution i found on internet but problem remains unsolved. Finally I tried following solution :

1. Right click on project in solution Explorer -> Properties
2. Click on to Web (On LHS).
3. Look at local IIS Web Server (Which would be radio btn selected by default).
4. Change port no of project Url e.g : http://localhost:1030/ to http://localhost:45896/ (Possibly Higher than 1024)
5. Save changes and run application.

This makes changes in IIS config files and wherever needed automatically so we don't need to change any code explicitly. That's work for me hope will work for You too.