Apple announced macOS 12 version 12.0, "Monterey," on 07 Jun 2021, for release on 25 October 2021. New Macs are shipping with Monterey starting 25 October 2021. Monterey is a free update to Big Sur.
Apple released macOS 12.1 on 14 dec 2021 fixing security problems and adding features.
Apple released macOS 12.2 on 27 jan 2022 fixing security problems.
Apple released macOS 12.3 on 15 mar 2022 fixing 45 security problems. It had issues reported.
Apple released macOS 12.3.1 on 31 mar 2022 fixing 2 security problems, Bluetooth, and display issues.
Apple released macOS 12.4 on 16 may 2022 fixing 54 security problems, many apps, and many library fixes.
Apple released macOS 12.5 on 20 jul 2022 fixing security problems.
Apple released macOS 12.6 on 12 sep 2022 fixing 8 security problems.
Apple released macOS 12.6.1 on 04 nov 2022 fixing 7 security problems.
Apple released macOS 12.6.2 on 14 dec 2022 fixing 13 security problems. Safari was updated too.
Apple released macOS 12.6.2 on 23 jan 2023 fixing 14 security problems.
Apple released macOS 12.6.4 on 27 mar 2023 fixing security problems and updating firmware. Safari was updated too.
Apple released macOS 12.6.5 on 10 apr 2023 fixing security problems and updating firmware.
Apple released macOS 12.6.6 on 18 may 2023 fixing security problems and updating firmware.
Apple released macOS 12.6.7 on 21 jun 2023 fixing security problems and updating firmware.
Apple released macOS 12.6.8 on 24 jul 2023 fixing security problems and updating firmware.
Apple released macOS 12.6.9 on 11 sep 2023 fixing security problems.
Apple released macOS 12.7 on 21 Sep 2023 fixing security problems.
Apple released macOS 12.7.1 on 25 Oct 2023 fixing security problems.
Apple released macOS 12.7.2 on 11 Dec 2023 fixing security problems.

The latest version of macOS is version 14.4.1, "Sonoma", relesed on 25 Mar 2024.

I skipped installing Monterey. I have Ventura installed on several computers.

Here is a review of Monterey from Ars Technica.

Show Stoppers

From MacInTouch: "Appleā€™s macOS Monterey 12.3 update yesterday drastically impairs performance of some graphics cards, according to reports." "Also macOS Monterey 12.3 Update Bricking Macs That Have Had Logic Board Replacements." Presumably fixed in later releases.

As of 04 Dec 2021, there were multiple severe problems. It appears that macOS 12.1 fixes some of these, but not all. A firmware update for M1 Macs is included with 12.1. Check MacInTouch for the latest status. There are severe slowdowns. There are bugs in charging, disk mounting, Mail and Finder freezes, mail searching, and drive formatting. Howard Oakley reports that there are 4 memory leaks in Monterey. Fixed in later releases.

There were also reports of charging problems on Apple M1 MacBook Pros. and issues mounting and writing to some SD cards.

Features of Monterey

Some applications developed for iOS can also run on Monterey; this may make more apps available for the Mac. This feature is called "Catalyst."

Monterey cryptographically signs every file on the read-only file system partition (that was introduced in Catalina). The signatures are checked when files are loaded, and the bootloader checks that all the hashes are correct at boot time. This should make it more difficult for malware to patch the OS.

Should I Install Monterey?

Installing Monterey on an Old Mac

Intego has a web page that explains how to run OpenCore Legacy Patcher to install Montrey on Macs that are "too old." See This is extremely scary to me. There are 26 steps. If Apple stops fixing security buts in Big Sur I guess I will have to do this.

What you Should Do Now to Get Ready for Monterey

Who Can Update

Not everyone can use the new OS version.

Plan your install

When you decide to install Monterey, do it carefully. You may find that there are issues that affect you: do your homework. Check MacInTouch to see if there are problems with macOS 12.0 that affect you.

Make sure you back up your entire disk before starting to install Monterey. Preferably to more than one place.

Make a list of the hardware you depend on, and search the web to check that each device will work. Older printers and scanners can have issues.

Leave yourself enough time. Upgrading will tie up your computer for a big part of a day. Installing takes an hour or two, but then your computer will be very slow until it re-does the Spotlight index and does a big backup up to Time Machine.

Particular issues before upgrading


Here is a partial list of minimum program versions needed for Monterey. For other programs, check product websites.

ProgramMinimum VersionNotes
Aquamacs Emacs3.6graphics issues
Audacity3.0464-bit at last
Adobe PhotoshopCC Photoshop CC is $120/yr. See below. (ARM supported.)
Adobe IllustratorCC Illustrator CC is $240/yr. See below. (ARM supported.)
Apple XCode13.1 free with registration; also install Command Line Developer Tools
Little Snitch5.3.1 A new version of Little Snitch is required for Monterey. Furthermore, some Apple traffic such as Maps and ads don't show in Little Snitch. This sucks.
Brother HL-4150 driver Brother does not support this printer, according to their website. Apple no longer maintains
Brother HL-5450DN driver Brother does not support this printer, according to their website. See above.
Homebrew3.3 for Monterey Replaces MacPorts.
Microsoft Office2021 $129
Onyx4.2.5 free
Quicken2018 $35/yr. See below.
Super Duper3.5
Brother P-Touch Editor5.1

Adobe: Renting Instead of Buying

Adobe no longer sells regular application versions of Photoshop, Illustrator, and Acrobat. Instead they rent you a Creative Cloud subscription. Stop paying, the apps stop working. They tell you that one advantage is that you'll get bug fixes and new features whenever they decide to release them. (There are a lot of tricky deals, initial teasers, different bundles. You could pay $20/app/mo or $600/yr for all CC apps, plus $180/yr for Acrobat. Adobe also sells Photoshop Elements 2020 and Premiere Elements 2020 as non-cloud applications for $100 each one-time, or both for $150.)

There are alternatives to Adobe products. I am using Affinity Photo and Affinity Designer. I need a replacement for Adobe Acrobat: PDFPen ($80) is looking attractive. There is a program called PDF Expert but its web site does not say how much it costs. I am not going to install it just in order to find out.

Microsoft: Renting Instead of Buying

Microsoft wants to rent you "Office 365" for $70/yr, $100/yr for up to 6 people. You can still buy a "forever" Home and Student version of Office 2019 for about $130.

Quicken and Banktivity: Renting Instead of Buying

Quicken has moved to a rental model also. There are various versions, Starter, Deluxe, Premier. Banktivity 7 works for me and is not rental software. Update: Banktivity 8 is going to a subscription model as of 2021. Shucks. Maybe I will look at GNU Cash.

Installing Monterey

(I have not installed Monterey yet, so everything below this point will need updating when I do.)

  1. Clean up and update software before installing.
    • (If your Mac is running a very old version of OS X, you must install Snow Leopard 10.6.8 first, in order to get a version of Apple App Store that can download Monterey. Here is Apple's how to upgrade page.)
    • You can download the Monterey Installer from  ► System Preferences... ► Software Update. It is free. This downloads a large file, the Monterey Installer, to your disk. You can create a bootable installer volume on a USB key using these instructions. (But see the TidBits article "Previously Downloaded OS X Installers No Longer Work".) Apple's license terms say you can update all your computers with one purchase.
    • Get the applications on your computer ready for 12.0: apply the latest fixes.
    • Delete junk files. Carefully.
    • Delete Safari, iTunes, and Firefox caches, so your backup will be faster.
    • If you have customized your desktop background or screensaver, write down your settings. Some Apple-provided pictures may not be available in the next version.. make a safe copy of anything you will want after upgrading.
    • Empty the Trash.
    • Clean up damaged and duplicate fonts.
    • Have your software license keys handy in case you have to re-authorize products.

    For Programmers

    • If you use MySQL, back up your databases with mysqldump databasename > db.sql. Then stop MySQL.
    • If you use Apache, save a copy of /etc/apache2/httpd.conf.
    • If you installed modules via CPAN, Macports, or Fink, make a list of them. In a Terminal window, type
      perldoc perllocal | grep :: > cpan_modules.txt
      port -qv installed > macports_packages.txt
    • The best way to handle Macports is to uninstall all the old ports and reinstall after updating the OS. After you list your installed ports, type
      sudo port -fp uninstall installed
      in a Terminal window.
  2. Backup and prepare.
    • BACK UP YOUR HARD DRIVE to an external disk. I used SuperDuper to clone my whole drive. Some cautious people make two backups.
    • If you are using an anti-virus product like Microsoft Defender ATP, disable it, or installation will fail. Some anti-malware programs see the utility that converts HFS to APFS as malware, and prevent it from running. Since most anti-virus software is tightly integrated with the operating system, you may have to install a Monterey-specific version of your software after installing Monterey anyway. Check with the maker of your software.
    • If you installed a third-party Solid State Disk (SSD), check the manufacturer's website to see if you need to update its firmware to work with Monterey.
    • If you connect your Mac to the network using WiFi, select  ► System Preferences... ► Network ► Advanced and delete any WiFi networks you don't want to use. (If you don't, your computer may connect to a very slow network during installation, which will slow down your install.)
  3. Install
    • If you use a wireless mouse or keyboard, put in fresh batteries.
    • Set screen saver to NEVER, and turn off Time Machine.
    • Dismount and unplug or power off external drives.
    • Restart your computer. (I've had problems where my computer hangs on shutdown. Restarting seems to fix it for a while. Don't want this trouble when installing a new OS.)
    • Run the Monterey (macOS 12.0) installer. If you downloaded it, use that copy. Or you can just select  ► System Preferences... ► Software Update and install by clicking on the link.
      • If FileVault is enabled on your computer, the installer will ask for a password to unlock the disk.
      • The installer will run for about 15 minutes, then reboot, then run for about an hour, then reboot again. Might ask for your password again.
      • The "time remaining" will show wildly varying estimates as the installer proceeds.
      • Don't panic if you see a gray screen with "30 minutes remaining" for an hour. Just let it run.
      • Eventually you will be presented with a login screen; enter your password.
      • You will see a window about privacy.
      • Next you will be asked if you want to send analytic information to Apple.
      • Then you will be asked if you want light mode or dark mode appearance. (You can change this later.)
      • Then the system will display your desktop. All your files and applications should be there.
    • If Monterey asks you if you want to "enable Desktop and Documents folder syncing to iCloud," the safest thing to do is to say NO. If you say YES, these folders will be backed up in iCloud and available on all devices, which you may not want, and saying YES may also enable "Optimize Storage" without asking, which will delete files from your computer's drive if it gets too full. Adam Engst's TidBITS article on Optimized Storage is very helpful.
    • Select  ► System Preferences... ► Software Update and  ► App Store... to make sure you are up-to-date with the latest versions of Apple software. Then run it again to make sure all software is updated. (might take another hour) This step may find additional OS and application updates.
    • Do a "smoke test" to verify that your computer is working OK. Make sure the applications you depend on are still working. Try out the applications from Apple that were updated with the OS. If you have trouble, restore your backup and go back to the old OS version.
  4. Recover
    • Wait for Spotlight to finish indexing (may take several hours). Performance will suck till it finishes.
    • Turn on Time Machine and start your backup.
    • You don't have to repair disk permissions with Disk Utility any more. In fact, you can't; the option is gone.
    • Restart the computer. Often this speeds things up.

Post Install Tasks

Once you are satisfied that your computer works acceptably, and you are going to stay on Monterey, you can make some adjustments.


You will probably want to set up per-user customizations, such as your desktop background and screensaver. After each new OS generation this is something of an adventure; functions get renamed and moved around.

Security issues

Catalina reorganizes your startup disk so that MacOS is stored on a read-only file system partition. This means that transitioning to Monterey has to move things around, and that going back to Mojave or earlier will be difficult.

There are additional security checks done by Gatekeeper. macOS will insist that programs are "notarized" in order to run them.

Some kinds of security certificates are no longer accepted. These are the ones using SHA-1, which is deprecated.


Re-Installing Programming Tools

If you use your computer for programming, you'll need to re-install your tools, which may have release dependent parts. The order presented here worked for me.

  1. The default shell is now zsh, which appears to have an incredible number of features and options. (This appears to be a result of GPL licensing issues on newer versions of bash.) You can still use the old bash until you figure out how to change over, and if your scripts have a first line of #!/bin/bash you will still get bash. Here is an exhaustive comparison of shells. For example, zsh doesn't split parameter expansions by default, bash has a help builtin, there is no read -p prompt in zsh -- use read cmd\?prompt, arrays start on 1 (not 0) in zsh, commandonly search for external commands in zsh, there is no (simple) equivalent to ${foo^.} (uppercase only first character) in zsh.
  2. (check this) In Terminal, type the command java. If you don't have Java 8 installed, this action will bring up a dialog box: click More Info to bring up the Oracle JDK installation page in a web browser, and trigger the installation of the Java 8 JDK from Oracle over the Internet. (check this) Java is needed for Eclipse and for other Mac applications, such as OpenOffice, and VPN clients such as Cisco. Java is not dangerous, if you use it to run code you trust: using it to run web page animations has had some problems.
  3. Install the full Xcode package using the App Store, and then install the Xcode command line tools from the Xcode menu. This will take a long time, about an hour. (Just using xcode-select won't work for some complex installs, which look for system header files installed by Xcode.)
  4. MacPorts: see my instructions for MacPorts. Basically the procedure is to list your ports and uninstall them before upgrade, install the OS, reinstall MacPorts, and reinstall your ports. MacPorts will install new versions of Perl, Python, or Ruby required by ports: set PERL5LIB correctly or installs will fail with messages about variants. (In future operating system versions, this is where to install Perl, Python, and Ruby.)
  5. MySQL: Version 8.0.24 is supplied by Oracle for Monterey and Catalina. See the instructions for installing MySQL. If you dumped your database, reload it with mysql < db.sql. MySQL has to be installed before you can install DBD::mysql with CPAN.
  6. MaxMind: If you use Perl module MaxMind::DB::Reader::XS, you must download and install libmaxminddb from before installing the MaxMind module with CPAN. (I had trouble doing this. The instructions say to do ./configure but no such file is provided. Luckily the file left over from Sierra still works.) Install any other libraries that are used by Perl modules at this point.
  7. Perl/CPAN: If you use Perl and Perl modules, install them. Perl 5.26.2 is installed by MacPorts as it installs various modules. ==== check this, might be 5.28.1 ==== See the instructions for installing CPAN for a list of modules I use. This is the time to install Python and Ruby libraries also.
  8. Apache web server:
    • Apache 2.4.34 is provided with Monterey, but is not automatically started and there is no System Preferences interface to enable it. You can buy products like VirtualHostX or MAMP, or use Terminal commands.
    • The Monterey install will not carry over your old Apache customizations. diff /etc/apache2/httpd.conf against your saved copy and edit as necessary.
    • Start Apache using the terminal command sudo launchctl load -w /System/Library/LaunchDaemons/org.apache.httpd.plist. The -w means make it permanent across restarts. (I got a fussy message when I did this, but the web server was running.)
    • PHP 7.3.8 is shipped with Monterey but disabled in httpd.conf. You can enable it by uncommenting LoadModule php7_module libexec/apache2/ and restarting Apache. I sometimes enable PHP in order to debug programs that will be deployed in safe environments on other computers. If you enable it, be aware of the risks of making PHP available on the Internet from your Mac, and track and install security updates.
  9. Screen saver: if you patched the duration of a screen saver slide, as I did, you will have to reapply the patch. You will have to disable SIP to do this, and then re-enable it after patching.

Monterey Observations

I skipped installing Monterey. See my notes on Ventura, which I installed on several computers.

Bugs and Surprises in Monterey

The ditectory :{/usr/local/bin:} is not created by default on Monterey. It is needed for correct operation of Homebrew and Aquamacs. Use Terminal command sudo mkdir /usr/local/bin to create it.

Planning for the next version

The next macOS version, macOS 13, Ventura, will be released in Fall 2022.

Keep a list of the software and devices you use and depend on, so you can check that they are supported.

Home | FAQ © 2010-2024, Tom Van Vleck updated 2024-03-27 10:03