Apple has released a supplemental security update for Mac OS X El Capitan (the predecessor to macOS Sierra. According to Apple, it “fixes a kernel issue that may cause your Mac to occasionally become unresponsive.”
![](/wp-content/uploads/archive/239AAC97-6C24-44D2-9C4D-872C9B8526B7.jpeg)
![](/wp-content/uploads/archive/239AAC97-6C24-44D2-9C4D-872C9B8526B7.jpeg)
The update originally was released in December 2016, but has been reissued. You can obtain the update by launching the Mac App Store app, then checking for updates.