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      Unable to start program  An operation is not legal in the current   state

User · Answer

Today I got this error  and I just did a small workaround which was too simple    Close all of your chrome instances  that you might have opened before you opened Visual Studio  Now stop debugging and run your application again     You will not get the error again and if the debugger doesn t hit  refresh the browser again      Update  12-Dec-2018     I just tested this bug in Visual Studio 2019 preview  it seems like the bug is fixed now   Hope this helps

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Incase you are not able to resolve the issue in any other way  then try this it worked for me     Keep this below code into your web config file then rename value  yourwebformname aspx    lt system webServer gt       lt defaultDocument gt          lt files gt             lt add value  insertion aspx    gt          lt  files gt       lt  defaultDocument gt       lt directoryBrowse enabled  false    gt   lt  system webServer gt    else Try    lt system webServer gt       lt directoryBrowse enabled  true    gt   lt  system webServer gt

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For me the issue was signing into my Google account on the debug Chrome window    This had been working fine for me until I signed in   Once I signed out of that instance of Chrome AND choose to delete all of my settings via the checkbox  the debugger worked fine again   My non-debugging instance of Chrome was still signed into Google and unaffected   The main issue is that my lovely plugins are gone from the debug version  but at least I can step through client code again

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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

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

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

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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      This is a known issue already  and seems to have an investigation underway   Full information about JS debugging in VS 2017 here  https   blogs msdn microsoft com webdev 2016 11 21 client-side-debugging-of-asp-net-projects-in-google-chrome

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Either switch your browser in VS2017   Or open up a command prompt as administrator and do a tskill chrome about 10 times to make sure the app fully dies   Then try again   Sometimes it gets stuck on another process and even it needs to be restarted

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The other answers in my case did not work  I had to restart windows before I could debug the application again

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I use chrome s build in developer console tools to debug javascript so the answer marked solution works great for me  This is the weird error message i was getting from VS Community 2017 when trying to debug asp net app         An error occurred that usually indicates a corrupt installation  code   0x80040154   If the problem persists  repair your Visual Studio   installation via  Add or Remove Programs  in Control Panel    and it s   fixed now

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Solution with JavaScript debugging enabled From the Chrome browser  go to  Settings gt Advanced gt System and disable  quot Continue running background apps when Google Chrome is closed quot    IMPORTANT  The option above must be set for the correct Chrome User Profile   Visual Studio has its own Chrome User Profile  preferences you set when using your  quot normal quot  Chrome browser wont have any affect on the Chrome browser launched from VS  with JS debugging enabled     Run your project from VS with  quot Enable JavaScript debugging    quot  enabled  The Chrome browser should open and you ll get the error in VS  Go back to the same instance of Chrome that VS started and disable  quot Continue running background apps when Google Chrome is closed quot  as explained above  If you don t have  quot Enable JavaScript debugging    quot  enabled checked  the Chrome instance would use your Default User Profile and the error would persist  Stop and rerun your project  Chrome should load the project as expected without any errors and with JS debugging enabled   Whenever you stop debugging  you must close the Chrome instance initiated by VS or the error will return the next time you run the project  If there are other Chrome instances  you can leave these open  To make sure Chrome is using the correct User Profile  go to chrome   version  by typing it in the url bar  then look at the value for Profile Path  On Windows  the correct value should look something like this    quot C  Users  UserName  AppData Local Microsoft VisualStudio 15   WebTools ChromeUserData   Default quot  If Chrome is using the browser default or if you re logged in to Chrome with an account  it will look something like this    quot C  Users  UserName  AppData Local Google Chrome User Data  ProfileName  OR Default quot  Bonus note  If you use Chrome Extensions when debugging  these has to be installed when the VS Profile is active

User · Answer

Changing this project setting solve the issue for me

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

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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

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I think that this happens when javascript debugging is enabled in visual studio and at the same time the chrome developer tools debugger is enabled  The problem arises because two different debuggers trying to debug the same process

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I just closed all open chrome instances  stopped my project and then start it again  that fixed the problem for me

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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

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Another solution you can try that worked for me when I received this error is to clean the solution  then do a rebuild   As the other solutions did not help me  I thought this might help someone else in the same boat

User · Answer

I found a workaround to this which worked for me  With Chrome selected as your browser  click the Debug menu and select Attach to Process     In the subsequent dialog  select Chrome exe in the list and click the Select button for Attach to   Tick the Native box  then Attach  or just double-click Chrome exe    This starts the project running without launching the browser  Stop  and restart in Chrome and the error is gone  Of course  another potential solution is to use a different browser but I like debugging in Chrome   -

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I had the same problem after the most recent VS 2017 update  released March 14  2017  build 26228 09   My program would debug fine in IE but would bomb out in Chrome  Killing all instances of Chrome within the Windows command line fixed the problem for me   taskkill  im chrome exe  f   I was then able to debug in Chrome

[asp.net] Visual Studio 2017 error: Unable to start program, An operation is not legal in the current state

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