My saga about broken stuff after Windows 10 upgrade continues (it all started with Virtualbox).

Today’s heroes are Visual Studio 2015 and IIS Express 10 (which comes with VS 2015 and replaces the old version if you had one).

Problem

So I’ve got this error message when trying to launch a Web-Site project in a Visual Studio solution:

Y U NO ACCESS

The port it wants is free, so restarting Visual Studio won’t help, as well as restarting Windows. Running Visual Studio under the administrator does not help either.

There is an interesting thing in Event Logs - tons of error messages like this:

Unable to bind to the underlying transport for [::]:62600. The IP Listen-Only list may contain a reference to an interface which may not exist on this machine.
The data field contains the error number.

Notice the IP address part: [::] - I honestly have never seen this before. Googling this thing didn’t yield any meaningful results so I tried Bing (no kidding). I figured Bing might have a better index of Microsoft’s own resources and I was feeling lucky. :)

Here is what poped up at the top of the list and… “Bing!” :)

Turns out there is a place in Windows registry where you can see what URLs are allowed to be bound to services without admin privileges. The parameter is called ListenOnlyList and it needs to be set to the address that exists on your machine.

I didn’t have the parameter at all:

No ListenOnlyList

Solution

You need to configre this parameter by running the following in the administrative command prompt:

> netsh http add iplisten ipaddress=::

This should put the correct value in the registry:

Yes to ListenOnlyList

Do it and your IIS Express will be happy again!