Safari 9 - I cannot install extensions

Hello, I recently had this issue too but I solved it really quick, the easiest way to solve it is to go to Safari>Prefrences>Advanced>Show Developer menu in menu bar. Once you have done that go to the Develop menu bar and go to User Agent then Choose Safari 10.2 or anything above Safari 9.0. Hope this helps!

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Thank you. That was it for me to.
I was allready going crazy. Checked the right management, copied settings from a second machine.

And this simple way resolved my problem.

Please Apple, this appears like a bug. Please fix it.

This was driving me nuts and a particular app developer was of no help. Just kept emailing me back to go to the extension gallery link and install. Yep thanks but no install link. My fix with Avast anti-virus software installed on MacOS Sierra:

I went to Avast > Preferrences > Web Shield > Settings

Click on +

Add apple.com for HTTP (you might not require this one)

Repeat for apple.com for HTTPS

Reload Safari extension link page and now there will be an "install now" link.

Thank you all on this forum for pointing me in this direction.

I am using El Capital v10.11.6 (15G1510) on a fresh install and ran into this issue both on admin as an account with lesser privileges.

The workaround that worked for me was to start in Safe Mode (hold SHIFT key on start up).

Open Safari > Preferences > Extensions then click Get Extensions. Select and extension then click Install.

Extensions install directly from the Extensions gallery window now.

Disable the extensions you have now and try again.

I'm experiencing the same problem as the original poster. I've cleared all website data and uninstalled all my currently extensions. If I go directly to the extensions page (safari-extensions.apple.com), or get there via the "Get Extensions" button, the result is the same. I can see all the extensions, but none of them have install links. In the upper left part of the page is a link stating "Extensions in this gallery run in Safari 9.0 on OS X El Capitan and Yosemite. Learn about OS X El Capitan", which seems to indicate that Apple's site doesn't know I'm running Safari 9.

Well, that was odd. I chatted with Apple Support for a while and they weren't sure what was going on. Right after my support chat ended, a notification popped up to watch the "Welcome to El Capitan" intro slide show. I thought that might be worth watching because I've seen applications that update their state only after you watch some sort of intro slides or tutorial. The problem with the extension gallery seemed to be that Safari wasn't telling the extension gallery that I was running El Capitan and/or Safari 9, and I thought watching the slide show might flip a flag somewhere and cause my browser to properly identify itself. Sure enough, right after the slide show started, I went back to a tab showing the new extension gallery, refreshed it, and install links popped up.

This worked for me too, although I can't think of any explanation as to why it would!

You can trigger the "Welcome to El Capitan" slideshow via the Finder by going to Help | What's New in OS X.

I'm having the same issue. Running through the "Welcome to El Capitan" slideshow via Finder did not solve the problem for me. I still can't install any new extensions.

I'm having the exact same problem. This only happened to me on my Macbook Air. My iMac's Safari is working just fine. I've tried the ideas stated here by triggering the What's new on El Capitan slideshow but still, the extensions page seems to think I'm not on El Capitan and Safari 9 so there is no "Install now" button. I've even tried reinstalling OS X but I had no luck. Please help!

Try booting into the Safe Mode and see if you can install them there.

Safe Mode - About El Capitan

Safe Mode Startup – El Capitan.

I'm having the exact same issue, I tried doing the welcome to El Capitan and that didn't work, I am running RMB 2015. Please help.

I have OS X Yosemite 10.10.5 and Safari 9.0. I'm also having this problem. My thinking was I might have to upgrade to El Capitan to be able to install extensions, but I see others who have already upgraded are having the same issue. I'm a new Macbook user.. not the way I wanted things to start. I have tried to watch the tours of both Yosemite and El Capitan but the "Install now" links are still missing. I have tried going through Safari > Safari Extensions... and Safari > Preferences... > Extensions > Get Extensions and both fail to show the links to install. I have also tried repairing permissions. Any help to fix this issue would be greatly appreciated. Thank you.