Big Mac 2 - install macOS Monterey on an old Apple Mac Pro

With almost every new macOS operating system for the Apple Mac, older computers from the manufacturer are gradually falling out of the compatibility list. If you still want to take the step and install the latest system on a computer that is actually too old, you can use a so-called patcher. The software Big Mac 2 is a patcher intended to bring macOS Monterey to old Mac Pros. The open source project can be obtained free of charge from GitHub and, in addition to macOS 12 Monterey, can also handle macOS 11 Big Sur. Here are a few details about this.

TL; DR: You can download it directly here

If you want to install macOS 12 Monterey from 2021 on an old Apple Mac Pro from 2008 to 2012, Big Mac 2 will help you. Big Mac 2 also brings macOS 11 Big Sur to Mac Pro 3.1, 4.1, and 5.1.
If you want to install macOS 12 Monterey from 2021 on an old Apple Mac Pro from 2008 to 2012, Big Mac 2 will help you. Big Mac 2 also brings macOS 11 Big Sur to Mac Pro 3.1, 4.1, and 5.1.

Big Mac 2 installs Monterey and Big Sur on old Mac Pros

For macOS Big Sur there were already some offers last year that were supposed to bring the operating system to devices that are actually no longer supported. One of them was that Big Sur patchers, which we presented in the linked post. The download page shown at the time now states that the software is no longer being developed and is no longer offered. As an alternative, a link to the GitHub page from OpenCore Legacy Patcher given. But enough of the review, because whether Big Sur or Monterey - Big Mac 2 can do both.

The Big Mac 2 app gives you many options for fine-tuning the installation. You can select the preferred system (macOS 12 currently only as beta), download the system and create an installer, activate or deactivate various system functions and regulate compatibility with the installed hardware. Corresponding instructions and all screenshots can be found on the GitHub page from Big Mac 2. This should help you to install macOS Monterey on old Intel-based Macs.

Official and patched compatibility of macOS 12 Monterey

With Big Mac 2 you can install macOS 12 Monterey on an Apple Mac Pro 3.1 or 4.1 or 5.1. These are the models that came on the market between 2008 and 2012. Of course, it makes sense to take some time to prepare the old computers and to carry out the Monterey installation with the experimental software. Not only should you make a backup of the internal storage, you should also deal with the respective setting options of Big Mac 2. You can read here which Mac models are inherently compatible with macOS Monterey: Is my Mac compatible with macOS Monterey?

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5 Responses to “Big Mac 2 – Install macOS Monterey on Old Apple Mac Pro”

  1. Tried and it doesn't work. The MacPro3,1 does not even recognize it when starting with the Option key held down. It detected it from the startup disk in recovery mode, but when selected and restarted it fails to boot.

  2. It looks like the APFS ROM patcher needs to be installed first. The problem is that the instructions are vague and if the ROM is installed incorrectly it will destroy the machine. So that's obviously a bad move. The readme file does not tell you how to install the ROM on a machine with no operating system installed. So it's pretty much useless.

    1. Hi Dorian! Unfortunately, I can't comment on this because I don't use the programs. I'm not a fan of installing macOS versions on incompatible Macs. Most of the time you are doing yourself a disservice.

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In the Sir Apfelot Blog you will find advice, instructions and reviews on Apple products such as the iPhone, iPad, Apple Watch, AirPods, iMac, Mac Pro, Mac Mini and Mac Studio.