I have an old 2011 MacBook Air that is running the latest version of macOS Catalina thanks to the very wonderful Catalina Patcher by dosdude1. This project has made it possible for me to run and test some of the latest software from Apple - namely Safari 15.

I ran into a small bug early on though – Safari extensions couldn’t be activated via the preferences menu. Luckily I discovered a very simple fix. My hope is this might help others (as small of a demographic that might be) who run into the same issue with the Catalina Patcher.

  • Close/Quit Safari completely
  • Open the Finder and use the shortcut ⌘ Shift G
  • Paste the following to navigate to the proper folder: ~/Library/Containers/com.apple.Safari/Data/Library/Safari/AppExtensions
  • Open the Extensions.plist in your favourite text editor (I’m a big fan of Panic's Nova)
  • Below each extensions <dict> tag, add the following: <key>Enabled</key><true/>
  • Save the file and relaunch Safari

Reference of what it should look like (AdBlock for this example):

        <key>Allowed Domains</key>
        <key>Has Injected Content</key>

After following those simple steps you should have working extensions in Safari. Have fun on your old, "unsupported" Apple devices!