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

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.

Answer 2

I had the exact same problem that the OP states "This problem came from nothing."

And I simply just rebooted my machine and it worked again. Restarting IIS Express didn't work.

Answer 3

If this situation is sudden (everything works ok, but suddenly the error Unable to launch the IIS Express Web server is shown) the solution that often works for me is simply:

• Kill IISExpress process
• More importantly, close all browsers processes (Firefox, Chrome, Chrome Dev Tools, IE, etc)

Works like a charm :) If doesn't, try different solutions from this thread.

PS. I post it as an answer so it can be found easily, although someone wrote it here somewhere in a comment.

Answer 4

Remove your extra bindings from the config file.

run command prompt as an administrator and type.

1 . netsh http show urlacl

you will see a list of url that has been used, make sure the one you are trying to use currently is listed in this. in the next step you have to delete this reservation.

2 . netsh http delete urlacl url=/Your complete URL as listed in the list above/

after the acknowledgement, restart IIS

Answer 5

Try the following steps:

1. In VS2013 Opened Debug > Website Properties.
2. Select the "Web" tab.
3. Under "Servers" I found "Override application root URL" was unchecked. I checked it and saved.

Answer 6

Navigate to IIS express

cd "C:\Program Files (x86)\IIS Express\"

run this appcmd.exe list site /xml | appcmd delete site /in

Also, clear your temp files in %temp% and logout, or reboot

This will delete all the sites, enjoy!