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

One thing I have tried in the past when this type of thing happened is telneting to the port and doing a GET or HEAD:

telnet localhost 1900

Then type in HEAD and press enter. Sometimes the data returned shows something like a server name or an application name.

Answer 2

Just check there are two instance of vs2008 running in the sidebar.. :)

Answer 3

Just re-start the system , Problem would be resolved.

Answer 4

The problem was solved for me configuring NOD32 firewall to no longer see VS like a browser.

Setup>Antivirus & AntiSpy>Internet protection>HTTP

Just uncheck the vs, and the issue will be resolved.

I hope this finally helps.

Answer 5

Right click on the little "server page" running in your task bar, and click close. This usually happens when the DEBUG process terminates unexpectedly, or visual studio crashes. Try a really high port like 50000 and see if it works. There shouldn't be any processes using that port.

Answer 6

I had this same problem today and found a solution so I thought I would add my two cents:

My particular problem was that I would get the "Port in use" error message even though the development server was clearly running and I was able to use the application on it. As it transpired, I was working on a Web Service at the time and happened to have the design view open - without realising. It was this web service's design view that was trying to launch the development server - which is why I couldn't type a single character of code without getting the error.

Close your Web Service's design view... problem solved.

I sincerely hope this helps someone else someday too.

Cheers

Iain