Chrome Fix: Extensions, apps, and user scripts cannot be installed from this web site

On Google Chrome Canary, I have lately been getting the Extensions, apps, and user scripts cannot be installed from this web site error message when I was trying to install a userscript from userscripts.org, or an extension from a third party website. No matter what I did, it always displayed the Install Failure dialog and blocked the extension, app or userscript installation.

Update: The message has changed a bit. Chrome displays "Apps, extensions and user scripts cannot be added from this website" when you try to do so in newer versions of the browser

I first tried to download the file to the local PC first, to drag and drop it into the browser window to run a local installation, but that too was blocked by the web browser.

I have tested this in Chrome 19 and the browser did not block the installation, suggesting that only users of Chrome Canary, and maybe Dev, are currently experiencing the issue.

install failure chrome

It needs to be noted though that this has been implemented on purpose by the Chromium team, and that users who run stable or beta versions of the browser will eventually run into the same issues that Canary users are currently experiencing.

apps extensions user scripts cannot be added from this website

Why was it implemented

Off-store installations of extensions have been taken away mainly to protect the browser's user base from malicious extensions. It is one of those decisions that protects the clueless by punishing users who know what they are doing. Instead of switching off-site installations off by default, but providing users with the means to enable the feature again, Google decided to go all in and disable off-site extension installation completely.



According to one developer comment, the company overlooked popular user scripts in the implementation and has prepared a fix to resolve the issue.

This change was made to protect users. Off-store extensions have become a popular
attack vector for compromising users of larger sites (e.g. Facebook). Since the trend is only getting worse, we're putting the power back in the user's hands by allowing them to control where extensions are installed from. By default, the Chrome Webstore is the only source, but users and administrators will be able to add other safe sources as they see fit.

There you have it. Chrome users by default can only install extensions from the Chrome Web Store and no other location. Currently there is no option to add other "safe sources" to the browser, but it looks as if the team will implement the feature in a later version of the browser.

Read also:  First Chrome extension with JavaScript Crypto Miner detected

It will also be interesting if the browser will block extension installations from software installations, e.g. security software or toolbar installations, or if they will go through regardless of that.

Workaround

A workaround has been created, but it is not pretty. To bypass the protection, you need to download the extension or userscript to the local system. Once there, you need to drag and drop it into the page in the browser. If you drag and drop it elsewhere, nothing will happen.

When you drop it on the extensions page, you will notice an install option popping up there.

chrome drop to install

When you select that option, you will see the standard installation dialog that informs you about the rights that the script or extension is requesting.

Closing Words

I personally dislike the feature, and wish that the developers would add an on or off switch to it. I would not have an issue with it being set to off by default, if it would not be a issue to enable it again. As it stands now, it is making the life of extension developers and advanced users more complicated.

Update

A start-up parameter is making the rounds that you can use alternatively to enable off-site installations in the Chrome browser. For that, you need to start Chrome with the --enable-easy-off-store-extension-install parameter. Let me show you how you add that parameter to Chrome under Windows 7. If you have Chrome in your Taskbar right-click, hover the mouse over the Google Chrome entry there, and select Properties from the context menu.

If you are in the start menu, right-click on the Chrome link and select Properties directly. Append the command that you see above - with two dashes - to the end of the Target line there and save the settings with a click on ok.

chrome off-store extensions

When you start Chrome now you should be able to install extensions and userscripts from third party sites as well.

System administrators can set urls that are allowed to install extensions, themes and scripts in Chrome using the ExtensionInstallSources Policy.

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Responses to Chrome Fix: Extensions, apps, and user scripts cannot be installed from this web site

  1. votre June 12, 2012 at 8:03 pm #

    Once again the move towards walled-gardens and lock-in to a specific software source - all in the name of "protecting" the end-user continues apace.

    Welcome to Google's Brave New World.

    What happened to "Do no evil?"

  2. kurtextrem June 13, 2012 at 2:06 pm #

    A better fix:
    the switch "--enable-easy-off-store-extension-install"
    :)

  3. SWW13 June 13, 2012 at 10:25 pm #

    workaround don't work in chrome 21.0.1171.0 dev-m.
    "--enable-easy-off-store-extension-install" works, but you need two dashes at the beginning

    is there a issue about it?

    • Martin Brinkmann June 13, 2012 at 10:50 pm #

      I think I read something about the fix not working in some dev versions, not sure though anymore where.

  4. MaxArt June 14, 2012 at 8:45 pm #

    The switch didn't work for me, but the workaround did.
    Chrome 21.0.1171.0 dev-m.

  5. Zbob750 June 20, 2012 at 11:21 pm #

    I can confirm that this is also a "feature" in the DEV builds.
    I just noticed it and I'm running 21.0.1180.0 dev-m but it might have been in earlier versions as well

  6. dawit chernet June 25, 2012 at 10:09 am #

    that is good satisfacition

  7. Nick July 12, 2012 at 5:17 am #

    The workaround really isn't that big of a deal... just annoying that I had to spend time searching for the workaround.

  8. claudius August 3, 2012 at 4:15 am #

    i am using a dev version and the work around worked fine however, the file had a number in brackets at the end of the file name... it needed to be removed before dragging and dropping into extensions

  9. Marliece Morgan August 7, 2012 at 3:23 am #

    Google Chrome is playing "Big Brother" to protect us from evil extensions. Your Workaround performed flawlessly. You saved me from the dreaded "click monkeys". Many thanks.

  10. chan August 17, 2012 at 4:10 am #

    how about ubuntu user ?

  11. ipod123432 September 1, 2012 at 6:25 am #

    I cannot thank you enough for providing the information of the work around. It seems Google is indeed starting to play Big Brother, losing their nice start-up feeling and becoming more of an evil industry behemoth. Thanks again.

  12. Montague Keen September 5, 2012 at 9:23 am #

    Google is a part of "Big Brother" system, for a very long time.
    Thanks for this fix.
    It is working on Chrome Dev 23.0.1255.0.

  13. teg September 26, 2012 at 4:40 pm #

    when i do the drag and drop instead of installing chrome opens the text written in the user script

  14. Vierotchka October 12, 2012 at 11:36 pm #

    I successfully added the --enable-easy-off-store-extension-install and installed two extensions that I have been safely using for a long time, but now Chrome simply doesn't load pages but just hangs there. I have version 22.0.1229.94 m. In fact, ever since version 22.0.1229.94 m autoupdated, I have had nothing but problems with Chrome, even after clearing cache, cookies, uninstalling and reinstalling it numerous times. I'm in a world of hurt...

  15. Vierotchka October 12, 2012 at 11:38 pm #

    Also, restoring to previous versions works only for a short time as it quickly updates to the latest version.

  16. mastercicco October 31, 2012 at 8:35 pm #

    How about Ubuntu users? how do they do it, to bypass the Chrome-Store?

  17. otilia November 18, 2012 at 1:08 pm #

    thank you so much!

  18. Anonymous December 7, 2012 at 8:50 pm #

    Is there a workaround for IE

  19. Jituagni January 14, 2013 at 8:06 am #

    Thanks a lot dude...
    It really helped me to adding DAP extension in Google Chrome...

  20. Johan February 20, 2013 at 10:23 am #

    If I wanted a blocked device I would have gotten a Apple

  21. Felipe April 27, 2013 at 3:43 pm #

    Fuck you Google. What about Linux users?

  22. Shivanand May 23, 2013 at 9:24 am #

    Thanks. It worked

  23. shervin August 3, 2013 at 10:17 am #

    tnx very nice

  24. Dan October 11, 2013 at 9:40 pm #

    Thanks, this problem started happening to me last week but this workaround is great!

  25. MygGuy November 27, 2013 at 2:01 am #

    Thanks a lot!

  26. Windy December 3, 2013 at 1:22 am #

    This workaround does not work in Chrome version 31.0.1650.57 m . When you elect to install by dropping into the install box, a message comes up that says it can only be added from the Google Web Store. But if you try to do it from the Google Web Store, you get the dreaded message stating "Apps extensions and user scripts can not be added from this web site". This happen if you just drop it or if you elect to download direct from the link in the web store. Now what? Anyone have an idea for this circular problem?

    • kickbackcat March 27, 2014 at 10:28 am #

      Hi Windy, I've got the same issue as you, I'm on Version '33.0.1750.154 m' though, did you find a fix for this?

    • private pyle June 30, 2016 at 3:41 pm #

      The workaround does not work for me either.
      I noticed that I do not have quotes around the target as shown in the screenshot above:
      "C:\Users\kxo4\AppData\Local\Google\Chrome\Application\chrome.exe" --enable-easy-off-store-extension-install
      When I try to add them manually (to see if it might help), I click the apply button and it removes the quotes.
      *I am on a government pc which has lots of restrictions

  27. Molimus January 25, 2014 at 3:22 am #

    Thank you so much.

  28. Anonymous August 25, 2017 at 10:18 am #

    My workaround is to use Mozilla firefox and I had no issue. Time to move on. If Google can't provide this kind of service then I think it's about time to find an alternative.

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