Monterey 12.0.1, Big Sur 11.6.1 and Catalina Security Update 2021-007: a summary

If you haven’t yet installed any of the updates and upgrades released by Apple on 25 October 2021, here’s a quick summary and some matters arising.

Monterey 12.0.1

If you’ve just got one of the new M1 Pro or M1 Max MacBook Pros, Apple strongly recommends that you install this update as soon as possible. It fixes several significant issues in the otherwise-unreleased Monterey 12.0 which comes pre-installed on the first shipments of these new Macs.

If your Mac is currently running Big Sur, then I strongly recommend that you upgrade to Monterey soon. Big Sur hasn’t had any non-security bug fixes since 11.5.2, which was released on 11 August, over two months ago. Many of those bug fixes are included in Monterey, as are all the latest security updates.

Upgrading from earlier versions of macOS will inevitably be more traumatic, and there’s a greater risk of things going wrong. However, I still believe that if you can break free from 32-bit apps and Mojave (or earlier), the new Sealed System Volume and other structural features in Monterey are well worth the effort of upgrading.

There is, though, one warning of a potential problem when upgrading to Big Sur or Monterey from High Sierra, Mojave or Catalina. In some rare circumstances (presumably a bug in the older macOS) exceedingly large numbers of files in one of the working directories in /private/var/folders could cause the upgrade to fail completely. Mr Macintosh has full details of how to deal with this, and the quick test he recommends is running
sudo find /private/var/folders/*/*/C/ -type d | wc -l
in Terminal to check whether that returns a number greater than about 20,000. If it does, then follow the instructions he provides for dealing with this issue before you try to upgrade.

There are inevitably plenty of horror stories already about upgrades that went badly wrong. What you never hear about are the vast majority which complete without glitch or hitch. If you do experience any problems, the first thing to do is restart your Mac. If that doesn’t clear the problem, then try starting up in Safe Mode, leaving your Mac a couple of minutes, then starting back in regular mode. Further suggestions are given in this article.

One trick which is of little use now is performing a clean re-install. This is because every bootable installation of Monterey (and Big Sur) is perfect throughout its System volume. Before Big Sur introduced the Sealed System Volume, it was easy for parts of the new system to have minor errors which could make a clean re-install a useful tool. Now, when the System has been installed, its integrity is checked and validated thoroughly by the hashes which build up to the Seal at the top – and that has to match the hash set by Apple for that version of macOS, or your Mac won’t boot from it.

All Macs on which Monterey is supported have firmware updates. These are now checked correctly by SilentKnight, and listed in this article.

Not all of Monterey’s many features are available on all supported Macs. This article gives a detailed breakdown if you’re unsure as to what your Mac should be able to use.

Monterey 12.0.1 comes in two basic installers:

  • an update from 12.0 for new MacBook Pro models, available through Software Update
  • a full installer, which is readily obtained from the App Store, then delivered through Software Update.

There’s no standalone updater, following the pattern established in Big Sur.

Apple’s list of security fixes included in Monterey 12.0.1 is here, and includes more than 35 items, with several vulnerabilities in WebKit and three kernel bugs.

After upgrading or updating to 12.0.1, your Mac should also receive an update to Core Services Application Configuration Data, which is tiny at 24 KB. This may not appear in Software Update, but is easily obtained through SilentKnight or LockRattler. There is also an accompanying Rosetta 2 update for M1 models.

Big Sur 11.6.1

This is the second security update for Big Sur, now that it has entered the first of its two years of security maintenance only. It therefore contains no other significant bug fixes. It’s available in two forms:

There’s no standalone updater.

Apple’s list of security fixes included in this update is here, and includes vulnerabilities in AppleScript, iCloud, zsh, and two kernel bugs.

Most if not all Macs on which Big Sur is supported have firmware updates, which are checked correctly by SilentKnight and listed in this article.

Catalina Security Update 2021-007

This continues the series of security updates, and is available through Software Update, or as a standalone installer package from here.

Apple’s list of security fixes included in this update is here, and includes vulnerabilities in AppleScript, zsh, and two kernel bugs.

Many of the Macs on which Catalina is supported have firmware updates, which are checked correctly by SilentKnight and listed in this article.