As we warned in “Security Update 2020-005 (Mojave and High Sierra),” (September 28, 2020), users of macOS 10.14 Mojave who installed Security Update 2020-005 experienced many issues, as well as documented by Mr. Macintosh. The problems included large increases in memory usage, slow boots, general system slowness, inability to create new users and more. Further discussion suggested that the issues may have been related to the installation of Safari 14.0 (released last week) prior to security update 2020-005.
Apple released the updates for both Safari 14.0 and security update 2020-005 on September 30, 2020. As of late October 1, 2020, the company released macOS 10.14.6 Supplemental update that actually only installs a fixed version of Safari 1
The first coverage from Mr. Macintosh suggests that the additional update fixes all previous issues.
Exactly what you see in Software Update depends on what you previously installed. Regardless, the practical result is to let Security Update 2020-005 (if available) and macOS 10.14.6 Additional Update Installation provide you with the updated Safari 14.0 and security update code. If you have previously installed Safari 14.0 or security update 2020-005, we recommend that you install this additional update immediately.
However, if for some reason you want to be on an earlier version of Safari, you should be able to install security update 2020-005, but not install the additional update.
We suspect that the new version of Safari 14.0 installed by the additional update only addresses the bugs that triggered all the issues after security update 2020-005 was installed. Quite a few have reported separate issues with Safari 14.0, and we’re guessing that Safari 14.0.1, now in beta testing, will address them.
Although Apple responded fairly quickly, it is still a black eye for the company to send a security update that caused such issues. In Apple’s defense, the situation was unusual, with issues with the separate Safari 14.0 update and was only revealed after the user installed security update 2020-005. Still, we hope Apple investigates how such major issues slipped through internal testing.
When we write about Apple operating system updates, we always try to give advice on when to install. It is now clear that we must continue to make such recommendations for Safari and security updates in the future. The specifications may vary with the severity of the fixed vulnerabilities, but in general we currently suggest that you wait at least a week before installing updates like these.