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In Chrome 20 and older versions, you could simply open any .user.js file in Chrome and it would prompt you to install the user script.

However, in Chrome 21 and up, it downloads the file instead, and displays a warning at the top saying “Extensions, apps, and user scripts can only be added from the Chrome Web Store”.


The “Learn More” link points to, but that page doesn’t say anything about user scripts, only about extensions in .crx format, apps, and themes.

This part sounded interesting:

Enterprise Administrators: You can specify URLs that are allowed to install extensions, apps, and themes directly through the ExtensionInstallSources policy.

So, I ran the following commands, then restarted Chrome and Chrome Canary:

defaults write ExtensionInstallSources -array "*"
defaults write ExtensionInstallSources -array "*"

Sadly, these settings only seem to affect extensions, apps, and themes (as it says in the text), not user scripts. (I’ve filed a bug asking to make this setting affect user scripts as well.)

Any ideas on how to install a private user script (that I don’t want to add to the Chrome Web Store) in Chrome 21+?

share|improve this question
Have you tried enabling developer mode in Settings -> Extensions? Not sure if its gonna work but you can give it a try. – Rhyuk Jul 19 '12 at 12:04
@Rhyuk Thanks for the suggestion. I had developer mode enabled, though — doesn’t seem to make a difference. – Mathias Bynens Jul 19 '12 at 12:05
How do I install a userscript? – Sathya Jul 19 '12 at 13:00

Start Chrome with the --enable-easy-off-store-extension-install switch.

To use a command line switch (from

On Windows:

  • Right click on your "Chrome" icon.
  • Choose properties
  • At the end of your target line, place these parameters: --enable-easy-off-store-extension-install
  • It should look like: chrome.exe --enable-easy-off-store-extension-install

On OS X:

  • /Applications/ --enable-easy-off-store-extension-install

  • For Google Chrome you'll need to escape spaces like so: /Applications/Google\\ Chrome --enable-easy-off-store-extension-install

On Linux:

  • chromium-browser --enable-easy-off-store-extension-install
share|improve this answer
You have to quit chrome completely, not just open a new window from the icon. (this is rubbish of Google btw) – Jonathan. Aug 16 '12 at 20:32
Yep, this is encroaching on "evil" territory IMO. – jnylen Nov 26 '12 at 3:33
This worked... :) The answer of @MathiasBynens didn't work on MacOS/Chrome25 – Lipis Dec 19 '12 at 1:18
It worked!! Very helpful, thanks!! – Joe Coder Feb 26 '13 at 19:57
I have a problem on windows – gstackoverflow Dec 18 '14 at 12:12
up vote 36 down vote accepted

The problem was that’s raw URLs redirect to a different domain. So, we have to use these commands instead:

# Allow installing user scripts via GitHub or
defaults write ExtensionInstallSources -array "https://**" "*"
defaults write ExtensionInstallSources -array "https://**" "*"

This works!

Anyway, this seems to be a workaround (thanks to Paul Horn for the hint):

  1. Download the user script.
  2. Open chrome://chrome/extensions/.
  3. Drag and drop the user script file on the page you opened in step 2.
share|improve this answer
This seems better than having to edit the command used to open Chromium. Thanks! – btleffler Sep 3 '12 at 21:39
@btleffler Except that you'll have to jump through that hoop every time, rather than making the change once. – Eugene Beresovsky Sep 24 '12 at 23:48
NB. When drag and dropping, you need to drop the file exactly onto the message. Anywhere else on the page won't work. – Colonel Panic Oct 26 '12 at 10:53
is the drag and drop way of adding extensions still working? It does not seem like that on Chrome 24 on OSX. – Viktor Feb 20 '13 at 20:31
It bears mentioning that github allows the hosting of user-generated content on <username> (via "Github Pages" - Just a heads up for anyone for whom this would be a security concern. – mh. Mar 16 '13 at 13:27

Well, this took a couple hours of my life to figure out. I guess Google engineers think that we only deserve to install untrusted extensions if we can figure out how to do tricks and jump through their hoops.

The instructions in Mathias's answer look to be spot-on for Mac OS X, but I use Linux. Here's what I did on Linux to enable easier (pre-Chrome-21-style) install of all third-party extensions, apps, and user scripts from any website:

  1. Create the policies directory (if it doesn't already exist):

    sudo mkdir -p /etc/opt/chrome/policies/recommended/
  2. Create the policy file:

    cd /etc/opt/chrome/policies/recommended/
    sudo tee easy_install_extensions.json <<EOF
        "ExtensionInstallSources": ["<all_urls>"]
  3. Restart Chrome. Completely exit the program via menu -> Exit; don't just close your current window.



  • <all_urls> (used above) is a special pattern according to the URL match docs. Good to know about.
  • According to the Linux policy docs, the directories /etc/opt/chrome/policies/{managed,recommended}/ contain JSON policy files. If entries conflict, managed overrides recommended.
share|improve this answer
I didn’t know about <all_urls> — very useful. Thanks! – Mathias Bynens Nov 26 '12 at 6:59
Confirmed to work in Fedora 18. Awesome post, extremely helpful! – ehime Feb 21 '13 at 20:13
Awesome! Drag and drop didn't work before, and now it works! – billyswong May 29 '13 at 3:47

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