Visual Studio 2017 - Unable to start program http://localhost

For me, the solution (workaround) is to turn off JavaScript debugging on Chrome, which I believe is a new feature introduced in VS 2017.

Go to: Tools > Options > Debugging > General and turn off the setting for:

Enable JavaScript Debugging for ASP.NET (Chrome and IE)

Solution Make sure any previous opened Chrome debugging windows are closed before you start a new debugging session

Explanation When I started debugging from VS2017 a new Chrome window opened and when I stopped debugging the Chrome debugging window were shut down and then I could start debugging again.

If the Chrome debugging window wasn't shut down upon debugging stop for whatever reason, and I started a new debugging from VS then it opened a new tab in the previously opened Chrome debugging window, and I had the error and couldn't start debugging.

So I closed the debugging window manually before I started debugging and it worked again.

I just had the same problem, solved it by restarting Visual Studio 2017.

The problem solved by following setting VS-2017 -> Tools -> Options -> Debugging -> General: Uncheck/Disable the "Enable JavaScript Debugging for ASP.NET (Chrome and IE)" option

I tried the other options provided above such as Restart VS-2017, closing browser opened earlier but that didn't solved this problem. I have installed VS-2017 Community Edition one week back only.