Safari 9 - I cannot install extensions

It's not pretty but I moved every file in ~/Library/Safari to the trash and then quit and reopened Safari. After doing that extensions were able to install. And I guess you could put back the bookmarks and history files if they are important

Can anyone else confirm or deny josh2197's solution? I have been watching this thread for a solution.

Just to be clear. Did you move only the files in '~/Library/Safari' to the trash or the folders as well?

I've totally reset Safari (as described here), and gone through the "What's New in OS X" and am still unable to install extensions, but still have the same problem.

It seems to me like a bug, if not in Safari, then in the code on the Extensions Gallery page. I've filed a bug report with Apple, so hopefully it will be fixed.

For the record, manually installing extensions which are available for download separately does work OK so, for example, I can download 1Password extension and install it by double clicking.

Just the files in that directory

I can verify this. I've done this before and it worked, but not this time.

To further isolate the problem, I logged in as a Guest User, opened Safari 9 and discovered the Install Button is displaying in the Safari Extensions Gallery. I was able to download extensions successfully. This obviously means the problem is connected to my User ID when I log in. Can you do the same thing when you log in as a different user? If so... chime in. Does anyone know how a User account is connected to the Safari Extensions Gallery and how the rules work for displaying the Install Now button/link?

This solved my problem:

I had to remove everything from ~/Library/Keychains. Lost all my passwords but I had them stored in iCloud keychain. A few, I had to enter again.

Extensions - Can't see INSTALL NOW button in Safari 9

I was able to fix it by deleting all of the .plist files relevant for Safari - that may be another option in the future if anyone is a bit twitchy about deleting their whole Keychain. 😉 The one thing to remember to do in that case would be to export bookmarks.

I had this same issue and spent a few hours with AppleCare to no avail, so it was eventually submitted to the engineers further troubleshooting. It's been a minute since then but just now I figured it out. Here's what worked for me: After updating to El Capitan, I reinstalled Avast, a third-party internet malware program that provides three levels or "shields" of security, one of them being "Web Shield." I disabled Web Shield protection and restarted Safari and voila, "Install Now" suddenly reappears! I re-enabled the web shield and now it's all good.

Hope this works for you guys as well.

I have the OTHER version of the problem... -_-

I can install from the store / Safari Ext. page but I CAN'T install from .safariextz files (and so I can't use 90% of the interesting ones...) When I clic a file, it opens the dialog box where I should clic the "yeah yeah I trust this ext.", I do it. Box close. Nothing happened. Ext not in the panel, not copied in the folder.

Tried to wipe keychain, etc. nothing worked. And this is on a CLEAN installation... -_- (I Have a cloned HD with the old installation btw)

Any idea welcome. 😟

I have the same problem.

On my macbook (clean installation)

and on my iMac (updated from Yosemite).

Just a quick question : do you use little snitch or another firewall or maybe an anti-virus ? I managed to find only that possibility after countless reinstallation / new users to track the problem... I need to run more test (and lose more time...) to be sure but if you don't that means something else is at play. I'm pretty sure now that's a problem with the keychain though...

No, I don't use anti-virus, firewall, etc.

I haven't imported passwords in the clean installation, so maybe the keychain is the problem, but I don't know...

Thx for the answer. It may be a very weird OS X bug, but I'm trying to check if we can avoid it anyway... 😟

I submitted a bug report to Apple. The good news is that they have acknowledged the bug. The bad news is that it's a duplicate of another bug (22952398) so they closed my report and I have no visibility on progress other than the fact that it is still open.

I was hoping that the 10.11.1 release might fix this, but alas not.

Hopefully Apple will fix this soon, but in the meantime downloading extensions from another Mac or outside of Apple's extension gallery and installing by double clicking on the extension seems to work.