Located at the bottom of the Safari Security Preferences is the Internet plug-ins section. It contains a check box that dictates whether or not add-ons are allowed to run in the browser. This setting is enabled by default. To prevent all plug-ins from running, clear the check box.

• Download AdGuard for Safari for macOS 10.12 or later and enjoy it on your Mac. ‎More than 21,000,000 AdGuard users enjoy the better, faster, and safer Internet. The ad blocker extension clears all ads in Safari and fights data tracking to protect privacy.
• What's the name of the plug-in? This resource will be a great starting point: How to use Internet plug-ins in Safari for Mac. This will guide you to Safari Preferences Security, where you may find more information about the plug-in that's causing the issue, and how you can temporarily disable it for testing.

Safari User Guide

If you installed a plug-in and notice that Safari runs more slowly, quits unexpectedly, won’t download files or has other problems, the plug-in may be the problem.

Quickly disable a plug-in

You can quickly disable or enable a plug-in. This is an easy way to check if the plug-in is causing problems.

Adobe Flash For Mac Safari

1. In the Safari app on your Mac, choose Safari > Preferences, then click Websites.

2. Do one of the following:

   • Disable a plug-in: Deselect the tickbox to the left of the plug-in name.

   • Enable a plug-in: Select the tickbox to the left of the plug-in name. For common plug-ins such as Adobe Flash Player, you also need to turn on the plug-in for each website.

Change plug-in blocking policies for websites

Safari Plugin For Mac

You can allow a plug-in for some websites and block it for others.

1. In the Safari app on your Mac, choose Safari > Preferences, then click Websites.

2. On the left, select the plug-in you want to disable.

3. For each website, click the pop-up menu on the right, then choose Off.

   For some plug-ins, you see pop-up menus for different websites, and you can choose to block each one individually. To block all other websites that don’t have individual settings, click the “When visiting other websites” pop-up menu, then choose Off.

Best Adblock For Safari Mac

If the problem is fixed, contact the developer of the plug-in to see if there’s a newer version.