Can't start site in IIS (use by another process)

Question

Check using netstat -aon or netstat -aon | findstr 0.0:80 in a command prompt to see which Process Id is LISTENING to port :80 and then watch for that Process Id (PID) in Task Manager with view->select columns-> process id checked. End that process, restart IIS and you are done. (Note: if you have Skype installed, try exiting that process first.)

In a modern Task Manager, you need to go on the Details tab to search for the PID. Or, as mentioned by @Nikita G in the comments, you can use this command to find the task from your command prompt:

tasklist /FI "PID eq 123"

Note: change 123 with the PID returned from the first command.

It is happening because a different process is using port 80, it may be a chat application on your PC like Skype.

First, change the default web site port which was 80 to some unused port (e.g. 8087). To achieve this right click the application and then click on 'Edit Binding'.

After this port change restart again. Now you can identify which process is blocking the IIS Port 80. To check this use netstat command which displays the details of port along with the process ID.

Sign out of Skype and try again. I have experienced the same issue and I just logged out of Skype and then reset my IIS. It worked for me.

You can also run this command to find out which application or service is using the port and then trace it down in Task manager (Provided it's not the Web Deploy Agent Service).

netstat -o -n -a | findstr 0.0:80

Then open Task manager, go to Processes, click the "Show processes for all users" checkbox and then click the View menu and Go to the Columns, add the PID column.

Match the Process ID from the netstat command to the PID in task manager and you will find the service or application that's using the port.

As others have said, something else may be using port 80 or 443. It was VMWare Workstation Server for me, but check other answers for how to use netstat.

I think this link gives a pretty good explanation and fix of this problem http://support.microsoft.com/KB/890015

Most of the time; it's caused by one of the two reasons: 1) port 80 is being used by something else and as suggested by others you can use netstat -o -n -a |findstr 0.0:80 to see whether this is the case. If yes then kill the process from task manager (tick show processes from all users)

2) if port 80 is not used, the second cause is potentially an invalid ip address in the ListenOnlyList filed in the registry key of HTTP->Parameters. If you follow the link to set the key manually or in fact you can use (xp and server 2003) httpcfg delete iplisten -i ipaddress to delete the invalid ip address. You must restart the http once you edit the ipaddress!