Unable to launch the IIS Express Web server, Failed to register URL, Access is denied

Question

Some web projects are causing me problems while others work fine. I decided to focus on one of the problematic ones. I\'m using Visual Studio 2013 on Windows 7. I think I\'m

Answer 1

After trying a number of suggested solutions without success I just rebooted my PC. After that the problem didn't occur anymore.

Answer 2

Running netstat -abn I noticed that the software "Duet Display" was reserving thousands of ports in the ~51000 range.

Closing it solved my problem.

Answer 3

I got the same issue when running my application from Visual Studio 2019 on Windows 10. After some time googling and trying various proposed solutions without success, I determined that the "Access Denied" error was a result of the port number my application uses (50403) falling in an "excluded port range".

You can view the excluded port ranges with the following command:

netsh interface ipv4 show excludedportrange protocol=tcp

After some more time googling I found that the two most likely culprits that create these exclusion ranges are Docker and Hyper-V. Docker was not installed on my computer but Hyper-V was.

My Solution

1. Disable Hyper-V: Control Panel-> Programs and Features-> Turn Windows features on or off. Untick Hyper-V
2. Restart the computer.
3. Add the port you are using to the port exclusion range: netsh int ipv4 add excludedportrange protocol=tcp startport=50403 numberofports=1 store=persistent
4. Reenable Hyper-V
5. Restart the computer

I added the port I am using to the exclusion list to ensure that I won't get this problem again after reenabling Hyper-V. After Step 4 and 5 when I viewed the excluded port range I can see that Hyper-V reserved a port range starting with the next port after my port.

My application now worked perfectly!

Answer 4

I solved this issue by killing all instances of iexplorer and iexplorer*32. It looks like Internet Explorer was still in memory holding the port open even though the application window was closed.

Answer 5

The ideal way to sort this out is to use the IIS Express tray icon to stop the web site that is causing the problem. To do this, click the little upward-pointing arrow in the right-hand end of the task bar and right-click the IIS Express icon. This will pop up a small window showing you the web sites that IIS Express is currently running...

If you click on one of the items under "View Sites" you have the option to stop that site. Or, you can click the Exit item at the bottom of the window to stop all web sites.

That should enable you to debug in Visual Studio. When you start debugging again, IIS Express will automatically restart the web site, and should be able to allocate the port.

If that fails, you have to do it the dirty way. Open Windows Task Manager and kill the Microsoft.VisualStudio.Web.Host.exe*32 process, then you can run the project fine. Note that this will kill IIS Express completely, meaning that all web sites will stop, so you'll have to restart each one in VS if you want to debug any others. Try the pop-up icon method first tough as it's cleaner and safer.

Don't know if this answers your issue, but it works for me.

Update Thanks to JasonCoder (see comment below) for adding that on Win10, the process is Microsoft.VsHub.Server.HttpHost.exe

Answer 6

If you're having this after installing Visual Studio 2015 and you can see Error messages in System event log such as this: Unable to bind to the underlying transport for [::]:{your_port}. . The IP Listen-Only list may contain a reference ... then you might be missing a registry entry.

Run this under administrative command prompt: netsh http add iplisten ipaddress=:: to fix it.

I found the solution described in detail here