Unable to launch the ASP.NET Development server because port '1900' is in use

Question

I was developing just fine in VS 2008 and testing my ASP.NET web site on my development server when suddenly I was unable to run my web site anymore. As soon as I hit F5, th

Answer 1

I had the same issue. The problem was that I also had IIS configured to use those ports. Stopping IIS or changing the ports used in the solution was may solution.

Answer 2

For a webforms site:

1. Remove the project from the solution.
2. Edit %userprofile%\Documents\IISExpress\config\applicationhost.config and remove the section for the problem port.
3. Add the project back to the solution.

Answer 3

I found a solution that doesn't require rebooting (for Windows 7).

Next to the clock, there's a tray of icons that is accessible if you click on the triangle icon that is next to the flag. Look for an icon with tooltip "ASP.net development server - port ###". Right click and select "stop"!

Answer 4

I had same problem, "unable to launch asp.net development server" The reason is virus program... I had disable it the it works properly...

I hope this helps...

Answer 5

You can check what software is running on given port by running netstat -o from the command prompt. It will give the Process ID (PID) of the process. I've had this happen after installing Skype, that was bound to port 80 before IIS could.

You can also check the eventlog for messages why IIS won't start. It might give enough information to solve the problem or to google it.

Answer 6

Set Cassini (Visual studio's lightweight built in web server) to use a different port. You can do this in the project's configuration dialogs