Unable To Launch Web Server
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 ?
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 :
- Right click on project in solution Explorer -> Properties
- Click on to Web (On LHS).
- Look at local IIS Web Server (Which would be radio btn selected by default).
- Change port no of project Url e.g : http://localhost:1030/ to http://localhost:45896/ (Possibly Higher than 1024)
- 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.
From the MSDN library
Visual Studio cannot guarantee that the port you specify will be available when you run your file-system Web site. If the port is in use when you run a page, Visual Studio displays an error message.
To change the port used by IIS Express to run your program you should follow the procedure outlined by this article on MSDN
How to: Specify a Port for the Development Server
In short, we need to edit the file %systemdrive%:\Users\<username>\Documents\IISExpress\config and change the binding information found in this file and change other configurations for the IIS Express.
As a consequence of this not so simple way to fix the problem, I recommend to close the application that tries to use that port access on you dev computer. Look for specific tools like TCPView from Microsoft that could help to spot the application that grabbed your port. Often it is only the browser
Run "netstat -b" from the command prompt to see what application is using port 4012. If you kill the process IIS Express will be able to launch using port 4012.
Killing the IIS Express Worker Process solves this for me; I run into this while trying to debug two concurrent instances of Visual Studio 2015 and switching between the two web solutions.
If this is a constant problem then Kedar's answer of modifying the solution is better, but in a pinch, for a code review, etc I prefer this.
One solution is to delete or clear the history in your browser. Then, restart the Visual Studio and re-run your application.
If this solution doesn't work, then it's time for you to change the port number for your development server (IIS Express).
I hope it helps you.