Security & Privacy

How to Install macOS Monterey on Unsupported Macs, for Security Improvements

Posted on April 19th, 2022 by and

macOS Monterey running on an old, unsupported, white MacBook (2009)
From a security standpoint, using the latest version of macOS—the Mac operating system—is essential, especially if you want to stay safe from actively exploited vulnerabilities.

However, if your Mac is several years old, there’s a good chance that the current version of macOS won’t run on your Mac; Apple drops support for Mac models that it declares to be vintage or obsolete.

If you wish to use the latest version of macOS but Apple no longer supports your Mac, the best option (in terms of speed, system stability, and the full range of Apple features) is to simply buy a new Mac. Of course, not everyone can necessarily afford to do so.

But what if there were a way to continue running the newest and safest version of macOS for much longer than Apple is willing to support your Mac model?

There’s hope for older Macs

There is, in fact, hope for users of many old Mac models. With a bit of effort, you can use a source-available, third-party utility that makes it possible for you to run the latest macOS version on significantly older hardware, with (for the most part) relatively minimal caveats.

According to Apple, these are the supported models for macOS Monterey (macOS 12.x):

MacBook (Early 2016 or newer)
MacBook Air (Early 2015 or newer)
MacBook Pro (Early 2015 or newer)
iMac (Late 2015 or newer)
iMac Pro (2017)
Mac mini (Late 2014 or newer)
Mac Pro (Late 2013 or newer)
Mac Studio (2022)

The list of Macs that can run macOS Monterey unofficially, however, looks more like this:

MacBook (Early 2008 or newer)
MacBook Air (Late 2008 or newer)
MacBook Pro (Early 2008 or newer)
iMac (Mid 2007, after upgrading the CPU)*
iMac (Early 2008 or newer)
iMac Pro (2017)
Mac mini (Early 2009 or newer)
Mac Pro (Early 2008 or newer)
Mac Studio (2022)
Xserve (Early 2008 or newer)

*With a processor upgrade (not for the faint of heart), the unofficial list can even include the mid-2007 iMac—a computer that is now about 15 years old.

The unofficial list looks impressive, doesn’t it? Perhaps it seems too good to be true, and to be fair, there are some known issues with certain models (see the OpenCore Legacy Patcher supported models list for details).

You might be wondering how such a thing could possibly work. In part, it uses a similar methodology to so-called “hackintosh” computers, where additional Apple drivers from previous versions of the operating system are included to make the current version of macOS work with a wider range of hardware.

Apple may not want to exert the effort to keep the latest macOS working on your old Mac hardware. (This actually makes a lot of sense, especially when you consider that Apple makes money by selling new Macs and doesn’t directly profit from macOS upgrades.) But thankfully, hobbyists are willing to pour a lot of hours into making new macOS versions work on older Macs without any support from Apple.

Preparing to patch

If you want to run macOS Monterey but can’t due to your Mac not being officially supported, here is how to go about it:

  1. First, go to your Apple menu and select “About This Mac.” Write down what it says next to “Model” (if it’s listed). Then click on “System Report…” (or “More Info…”). In the hardware overview window that pops up, a “Model Identifier” will be listed; write this down as well.
  2. Now that you’ve confirmed your Mac model, next you’ll need to verify that OpenCore Legacy Patcher works with your Mac by reviewing the supported models list.
  3. Back up all your data. Use Apple’s Time Machine and/or Intego Personal Backup, follow a “3-2-1” backup strategy, and ensure that your backups are really working.
  4. Grab a USB flash drive (or any USB/FireWire/Thunderbolt external hard drive) that can be erased and is 16 GB or larger in size. (Ideally, choose a fast external drive. This will save time when copying the macOS installer to the drive and booting your Mac from it during installation.)
  5. Download the latest version of OpenCore Legacy Patcher from this site. Be sure to choose the “GUI-Offline” version.
  6. If you normally use a Bluetooth wireless keyboard and/or mouse, it’s ideal to instead use a wired USB keyboard and mouse for this process. (If you’re upgrading a MacBook, the built-in keyboard and trackpad are fine, in most cases.)

As an aside, you can find many of the steps from this guide (and a few additional details) on the OpenCore Legacy Patcher site. But I’ll take the journey with you using my iMac (20-inch, Mid 2007, with an upgraded CPU) and add some helpful tips based on my experience. Mine is the oldest supported (er, unsupported) model, and it’s eight years older than the minimum iMac model that Apple still supports. (Note that I’m upgrading from a patched version of Catalina, but the steps below are the same regardless. The screenshot below is actually from another Mac running OS X El Capitan 10.11.6, which happens to be the final macOS version that Apple supported on my iMac, too.)

Although hardware upgrades are not usually required, you may wish to upgrade your Mac to the maximum amount of RAM and replace your hard drive with a solid state drive (SSD), assuming your Mac model is user-serviceable and you’re comfortable doing such upgrades. This will make your machine run much smoother.

Of course, it probably goes without saying, but Intego cannot provide technical support if something goes wrong. Proceed at your own risk.

Now that you’ve got everything ready to go, let’s begin!

How to install macOS Monterey on an unsupported Mac

Having completed all your prep work from the previous section, now you can follow this step-by-step guide to installing macOS Monterey on your unsupported Mac.

    1. Plug in your USB flash drive or external hard drive. (You’ll need this for later steps.)
    2. Open the “OpenCore-Patcher” app (the GUI-Offline version that you downloaded in step 5 of your preparation). Click “Open” if prompted.
    3. In the app’s main window, click on the “Create macOS Installer” button.
    4. A new window will appear listing many macOS versions. Click on the most recent non-beta version, which should appear near the bottom of the list.
    5. The macOS version you selected will begin to download. When the download finishes, you may be prompted to enter an administrator’s username and password “to add InstallAssistant” for the next step (this copies the “Install macOS Monterey” app to your Applications folder).
    6. Next, click on the “Flash Installer” button. You’ll then be prompted to choose the “Install macOS Monterey” app that you downloaded in the previous step. (If you have multiple options, choose the most recent version version of Monterey in the list.)
    7. You’ll then be prompted to choose your USB flash drive or external hard drive. (If you have multiple options to choose from, select carefully; the next step will completely erase the drive.) You may wish to write down the disk details; you’ll need to choose the same disk again later.
    8. Again, you may be prompted to enter an administrator’s username and password because “OCLP-Helper wants to make changes” (OCLP is short for OpenCore Legacy Patcher; this step allows for your external drive to be formatted).
      As explained on the “Creating Installer” screen, the process of copying data to your external drive can potentially take a very long time; this step took almost 90 minutes on my 2007 iMac.
    9. Once that process is complete, you’ll get a “Success” dialog box, and then you can click on the “Return to Main Menu” button.
    10. At the “main menu” window, click on the “Build and Install OpenCore” button.
      A new window will appear; click on the “Build OpenCore” button to continue.
    11. Once the text stops scrolling, the “Build OpenCore” button will change to say “Install OpenCore” instead; click on Install OpenCore.
    12. In the “Install OpenCore” window, click on the button for the same disk that you chose in step 7 above (i.e. your external drive).
    13. Next you’ll need to choose the partition. There should only be one button in this list (it will probably say “EFI” in the middle). Click on that button to continue.
    14. Again, you may be prompted to enter an administrator’s username and password because “OpenCore Legacy Patcher needs administrator privileges to mount your EFI.” This is necessary to prepare the external drive for the next steps.
    15. Moments later, you’ll see a bit of text, ending in “OpenCore transfer complete.” Your Mac is now ready to install macOS Monterey.
    16. Now it’s time to install the new OS on your Mac! Read this entire step carefully before you proceed; you’ll need to be ready to press buttons on the keyboard quickly. Click on the Apple menu, then select “Restart…” and click Restart again when ready. Immediately begin holding down the Option key on your keyboard (or “Alt” if you’re using a third-party USB keyboard). Immediately as soon as you see multiple drive options, stop holding the Option/Alt key, and use the arrow keys to choose the “EFI Boot” option with the blue-and-white OpenCore logo. Press the Return or Enter key to select this option.
      Next, use the arrow keys and Return/Enter to select the “Install macOS Monterey” option.
      Your Mac will start booting up from the installation disk. Depending on the age and speed of your Mac and your  external drive, this may take a few minutes.
    17. Once your Mac finishes booting, you should see the following options: Restore from Time Machine, Install macOS Monterey, Safari, and Disk Utility.
      Choose “Install macOS Monterey” and let the installer run as normal. In the pane where you’re prompted to select a disk, be sure to choose your Mac’s internal drive (e.g. “Macintosh HD”).
    18. After a while, your Mac will probably restart on its own. If it brings you back to the screen shown in step 17, just click on the Apple menu and select Restart, and immediately begin holding Option again. Select “EFI Boot” again, but this time you’ll need to choose the “macOS Installer” option with the internal hard drive icon superimposed (pictured below). This will allow the operating system installation to complete.
    19. When macOS Monterey has finished installing, there are just a few more steps remaining. First, you’ll want to set up your internal drive properly to ensure you no longer need the external drive attached. To do this, open the OpenCore-Patcher app (the one you used in step 2). From the main menu (as depicted in step 3), repeat steps 10 and 11 again to build and begin installing OpenCore.
    20. Although in step 12 you chose your external drive, this time you’ll instead select your internal drive (which is most likely disk0, but may vary depending on your Mac).
    21. Like step 13, there should only be one option that says “EFI” near the middle; click this button.
    22. Like step 14, you’ll prompted to enter an administrator’s username and password because “OpenCore Legacy Patcher needs administrator privileges to mount your EFI.” This is necessary to prepare the internal drive to boot without the external drive attached.
    23. Once you see a window similar to step 15, again you’ll see a bit of text ending in “OpenCore transfer complete.” Click on “Return to Main Menu” to prepare for the next step.
    24. From the main menu, click on the “Post Install Root Patch” button. (This will help you install any additional fixes that may be necessary to make Monterey work with your Mac’s legacy hardware.) Then click on the “Start Root Patching” button.
    25. When you receive the “Relaunch as root?” prompt, click Yes. Again you’ll be prompted for an administrator’s username and password, because “OpenCore Legacy Patcher needs administrator privileges to relaunch as admin.” The app will relaunch at the main menu, at which point you should repeat step 24. Then proceed to step 26.
    26. Once it says, “Patching complete,” you’ll also see the message, “Please reboot the machine for patches to take effect.” Before you reboot, drag your external (e.g. USB) drive’s icon from the desktop to the Trash to eject it, and then physically unplug the external drive from your Mac. Then click on the Apple menu, click “Restart…” and then click Restart. Hold Option/Alt one more time, and select the internal drive’s EFI Boot option.

You’re all set! Your Apple-unsupported Mac is now running macOS Monterey!

Installing macOS updates (minor and major)

The next time there’s a minor macOS update, i.e. a new version of Monterey, here’s what to do to ensure everything goes smoothly:

  1. Back up important files from your computer. (Refer to step 3 in the “Preparing to patch” section of this article for tips.) You should do this anyway, regardless of whether you’re using a Mac that’s supported or not.
  2. Run the OpenCore-Patcher app to check for updates. If it informs you that an update is available, download the GUI-Offline version.
  3. You should be able to install the macOS Monterey update like normal, via Apple menu > System Preferences… > Software Update.
  4. After macOS reboots, you’ll need to reinstall the Post Install Root Patch (steps 24 and 25 above), and then restart your Mac again.

Before you consider upgrading to a major new macOS version (e.g. macOS 13—which will likely be announced on June 6, 2022, and released in Fall 2022), you’ll need to wait to ensure OCLP is compatible first. Most likely an update to OCLP will be required before you can safely upgrade to the next major macOS version.

If the installation was successful and you’re thrilled to be able to run the latest operating system on your old Mac hardware, consider offering to donate hardware to the OpenCore Legacy Patcher developers to help them test updates more quickly on a wider variety of older Macs.

Additional tips

Now that you’re using macOS Monterey on an unsupported Mac model, here are a few more things you might like to know:

  • Back up your important files often. Not only are you running macOS in an unsupported manner, but your hardware is also quite old, so there is an increased risk of data loss. To keep your documents safe, you can use Apple’s Time Machine and/or Intego Personal Backup, use a 3-2-1 strategy, and confirm that your backups actually work.
  • Keep the external drive handy that you used for installing Monterey. You will need it for installing future major macOS updates, like macOS 13 (assuming, of course, that your Mac will be unofficially compatible with it).
  • Another way to stay aware of OpenCore Legacy Patcher software updates is to subscribe to Mr. Macintosh on YouTube. He releases a video for each new OCLP update and macOS update, so if you have any concerns about the process or want to be sure there aren’t any “gotchas” before you update, this is a good way to keep informed.

Welcome to the legacy patching community!

Congratulations! Your older Mac will now be able to keep up with the latest security updates. Although firmware updates are not included (those are model-specific, and Apple only releases them for supported Macs), your macOS will nevertheless be much more secure than it was with the old version of Mac OS X you were running before.

Every time a new macOS is released, I look forward to the next macOS Patcher, as it keeps our beloved—and still more than capable—old Macs around for just a while longer.

How can I learn more?

Each week on the Intego Mac Podcast, Intego’s Mac security experts discuss the latest Apple news, security and privacy stories, and offer practical advice on getting the most out of your Apple devices. Be sure to follow the podcast to make sure you don’t miss any episodes.

You can also subscribe to our e-mail newsletter and keep an eye here on The Mac Security Blog for the latest Apple security and privacy news. And don’t forget to follow Intego on your favorite social media channels: Follow Intego on Twitter Follow Intego on Facebook Follow Intego on YouTube Follow Intego on Pinterest Follow Intego on LinkedIn Follow Intego on Instagram Follow the Intego Mac Podcast on Apple Podcasts

About Joshua Long

Joshua Long (@theJoshMeister), Intego's Chief Security Analyst, is a renowned security researcher, writer, and public speaker. Josh has a master's degree in IT concentrating in Internet Security and has taken doctorate-level coursework in Information Security. Apple has publicly acknowledged Josh for discovering an Apple ID authentication vulnerability. Josh has conducted cybersecurity research for more than 20 years, which has often been featured by major news outlets worldwide. Look for more of Josh's articles at security.thejoshmeister.com and follow him on Twitter. View all posts by Joshua Long →