Q: Safari Share Button not working after El Capitan upgrade

Hello Emil,
 

Thank you for participating in the Apple Support Communities. 
 

It looks like after updating to El Capitan, Safari becomes unresponsive when you use the Share button. I see you followed some steps from another thread about removing Safari the preference file, but this didn't solve it for you.
 

Next, I'd like to see if the same behavior happens in safe mode or in a new user account on your Mac. These tests can help us determine what to try next, as mentioned in How to test an issue in another user account on your Mac. 
 

Start up in safe mode using the steps below, and see if the Share button works. If so, restart your computer normally and test again. 
 

If you're seeing unexpected behavior on your Mac try these steps first:

Try starting your Mac in Safe Mode. Restart your computer. Hold the Shift key when you hear the startup sound. Release the Shift key when you see the Apple logo appear. This starts your Mac in Safe Mode. Safe mode performs a directory check of your startup disk, and removes some cache data. After your Mac finishes starting up, restart your Mac normally (without holding the Shift key) and see if the issue is resolved.

If the same thing happens in safe mode, try a new user account next: 
 

How to test with another user account
 

You can figure out if unexpected behavior is related to user file or setting by trying to reproduce the issue from another user account. This process includes creating a new user account, logging in to it, and testing for the issue.
 

Create a test user account

1. From the Apple menu, choose System Preferences.
2. Click the Users & Groups icon in the System Preferences window.
3. Click the lock icon, then enter an administrator name and password.
4. Click the Add button (+) below the list of users.
5. Choose a type of user from the New Account pop-up menu.
6. Give the user a full name, account name, and password.
7. Click OK.
8. Close the System Preferences window.

Log in to the test user account

Log out of your current user account by choosing Log Out from the Apple menu, then log in to the new account you created. If you're prompted to sign in with your iCloud account or Apple ID when you log in, skip this step.

Try reproducing the issue

Try the same steps that caused the unexpected behavior to appear before. For example, if you were unable to print, try printing from this user account. If you were unable to connect to the Internet, try browsing a website from this user account.

Sincerely. 

Hi Bulgarus,
 

Thanks for replying with the results of the tests I mentioned.
 

Since the same thing happened when you tried in safe mode and a new user account, I'd recommend reinstalling El Capitan. You can use the "Reinstall OS X from Recovery" method in How to reinstall OS X on your Mac.
 

This process shouldn't affect the files in your user account, but it's a good idea to have a current backup before reinstalling OS X--Use Time Machine to back up or restore your Mac.
 

Best Regards. 

Hey Emil, you're welcome!
 

I'm glad that solved it. Thanks for letting us know.
 

Cheers.