Visual Studio 2017 error: Unable to start program, An operation is not legal in the current state

Question

After fresh installation of Visual Studio 2017 I tried to run .NET Core Web project and when trying to run it on Chrome I am getting this error:

Unabl

Answer 1

3 options

1. Turn off the JavaScript debug feature in Tools > Options > Debugging > General
2. Kill all chrome tasks
3. Switch to another browser to debug

Answer 2

I tried the answer by Sibeesh Venu, but that didn't work for me. I believe that if I had killed all chrome processes, it would have worked. I completed some other testing and found that turning off "Continue where you left off" in Chrome settings ensured that this did not occur again for me.

Answer 3

This error message appeared for me when I tried to debug two solutions at the same time as I wanted to visually compare the differences. Unchecking the Enable JavaScript Debugging for ASP.NET (Chrome and IE) option worked, but I am still confused why I could not debug more than one solution at a time. Since it is a known issue, maybe this will be address in an update from Visual Studio. Here is to hoping ....

Answer 4

I was able to solve this issue in Chrome by turning off the Calendly Chrome extension which I had recently installed. May not be Calendly specific so I would recommend turning off any newly installed Chrome extensions. Below are the steps I took:

1. Debug Program
2. Let Chrome Open and VS throw error
3. Clear VS error by clicking OK
4. Click Three dots in the top right corner of Chrome
5. Mouse over "More Tools" and click Extensions
6. Find Calendly tile and tick the slider in the bottom right corner to off position
7. Close all Chrome windows including any Chrome windows in the task the bar that continue to run
8. Stop debugging
9. Run program again in debug mode

Answer 5

What fixes it for me is to look in the task bar for open chrome apps, right click and close them.

Answer 6

I just recently had this error. What fixed it for me was to close a chrome window that was running the inspector. I have it pop out its own window whenever I inspect a web page. Did not need to disable or change anything on visual studio.