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

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"!

**Simply end all Webdev.WebServer.exe processes** - did the trick for me.
Occasionally this 'unable to launch because port is in use' error happens when one of the visual studio processes (webdev.webserver.exe) is still running and locked. The webdev.webserver process(s) should end when you close your browser or app but if they dont (for instance my Visual Studio crashed but if left the webserver still running) then this could lock the port and this will prevent visual studio from launching your project. When you try to F5 your app (launch your application from visual studio) then it conflicts with the current port in use and the above '*because port XYZ is in use*' error is displayed.

So to fix it: in the status bar (next to your windows clock) right-click and 'Stop' all the ASP.net development server icons. You can also open task manager and kill all the webdev.webserver.exe processes.

![enter image description here][1]


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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.

I simply stopped service MsDepSvc - Web Deployment Agent Service. Then I was able to run the site.

changing the port in Visual studio (Web) Project Properties for IIS express section solved the same problem for me


![Visual studio Project Properties for IIS express port in use problem][1]


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For a webforms site:

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

In the website portion of the project, right click and do "Properties Window" *NOT* "Property Pages" Change "Use Dynamic Ports" to TRUE. You can keep 80 there if it's the port listed--the key is to Use Dynamic Ports.

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.

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

In VS 2019, right click on project properties select Debug, scroll down to web server settings, change port number in AppURL
[![enter image description here][1]][1]


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