After trying again and again, I finally managed to install macOS Monterey on my 2012 MacBook Pro, even though it’s not officially supported. It took me about 24 hours to get it working!. At first, I kept getting errors while creating the installer with OpenCore Legacy Patcher. I tried many times, but nothing worked. So, finally getting Monterey installed felt like a big achievement!
This is an article about my experience installing macOS Monterey on a 2012 MacBook Pro using the OpenCore Legacy Patcher.
What Is macOS Monterey, and Why Should I Install It on My MacBook Pro 2012?
MacOS Monterey is version 12 of the operating system for Mac devices.
It was officially designed to run on Macs released in 2013 or later. So, older Macs, like my 2012 MacBook Pro, aren’t officially supported by macOS Monterey. However, with the help of a patcher, it’s still possible to install and run macOS Monterey on older Macs, including models released before 2013.
Why did I install macOS Monterey on a 2012 MacBook Pro?
As a CCTV technician, I need a newer version of macOS. This is because I need remote desktop applications like AnyDesk, which only run on macOS 11 or later. Instead of buying a new MacBook, which is quite expensive, I’d rather install macOS Monterey using the OpenCore Legacy Patcher—and learn a new skill in the process. What I like about the 2012 MacBook Pro is that it still has an Ethernet port. As far as I know, the latest MacBook models don’t have an Ethernet port and require an extension cable.
And as a CCTV camera technician, I need an Ethernet port to configure CCTV cameras. Besides, I don’t like using Ethernet extension cables.
How Long Does it Take to Install MacOS Monterey On a MacBook Pro 2012?
It took me 24 hours to succeed. That’s quite a long time.
Each device may encounter different issues when installing macOS Monterey on a 2012 MacBook Pro. If there are no errors, installing macOS Monterey using OpenCore Legacy Patcher takes 2 to 4 hours. The most time-consuming parts of the process are downloading the installer, creating the installation image, and the installation itself. Post-installation setup, on the other hand, doesn’t take very long.
Why Is It Taking So Long to Install macOS Monterey on My 2012 MacBook Pro?
There are plenty of installation guides on YouTube. Almost all of the instructional videos show the process going smoothly. But when I tried it myself, it wasn’t what I had imagined.
I always get an error message when creating an installer.
The error message I received while installing using OpenCore Legacy Patcher is shown below.
I think it’s because my USB is having problems.
However, when I bought a new flash drive, a similar error message still appeared when I tried to install it. I also tried following the instructions I found on a forum—manually creating bootable media by typing commands like this—but that didn’t solve the problem. Eventually, I found the solution.
How I Installed macOS Monterey on a 2012 MacBook Pro Using the OpenCore Legacy Patcher
All the error messages that appeared on the first try disappeared after I reinstalled macOS Catalina on my MacBook Pro. Yes, my MacBook Pro was previously running macOS Catalina, which is macOS version 10.
After I reinstalled my Mac, I then downloaded OpenCore Legacy Patcher.
I installed macOS Monterey on this 2012 MacBook Pro in August 2026. The OpenCore Legacy Patcher I used was version 2.4.1. Check out the complete guide I’ve provided below for installing macOS Monterey on a 2012 MacBook Pro or any MacBook model manufactured in 2015 or earlier.
Step 1: Download and Install OpenCore Legacy Patcher
Go to this page to download the OpenCore Legacy Patcher.
It’s possible that the version of OpenCore Legacy Patcher you downloaded is newer than the one I used in this guide. However, the way it’s used isn’t much different—only the interface layout is different.
On the download page, scroll down and find “Assets.”
Select OpenCore-Pather.pkg.
The download will then begin; please wait until it finishes. Once it’s finished, click the OpenCpre-Patcher.pkg file. Then drag it to the Applications folder. This completes the download and installation of OpenCore Legacy Patcher.
Step 2: Download the macOS Monterey Installer
Open OpenCore Legacy Patcher.
In the Opencore Legacy Patcher app, select “Create macOS Installer” > “Download macOS Installer” > Select the version of macOS you want; in this guide, I’m choosing Monterey. Click the Download button.
The download will begin.
Because the macOS Monterey installer file is quite large, the download process takes quite a long time. When I downloaded it, it took me about 1 hour and 45 minutes. The download will be faster if your internet connection is faster than mine. At the time, my internet connection had an average speed of 6 Mbps.
Step 3: Creating an Installer
Once the installer file has finished downloading, the “Extracting macOS Installer” process will begin; please wait about 10–15 minutes. At this stage, connect your USB drive to your MacBook. I’m using a 16GB SanDisk Cruiser Blade USB drive. Choose a drive size appropriate for the macOS file size. The macOS Monterey file size is around 12GB, so a 16GB USB drive is suitable.
A dialog box like the one below then appears.
The dialog box below indicates that the download is complete. Do you want to create a macOS installer on your USB drive? Select Yes.
Click OK and select your USB drive.
Click OK in the information dialog box to confirm that you have selected the USB drive to be used to create the installer. The installer creation process will begin; this will take more than 1 hour. While waiting for the process to finish, you can go about your other activities, such as watching TV or doing something else.
The installer is finished once the “Successfully Created the macOS Installer” notification dialog box appears.
Step 4: Installing OpenCore on a USB Drive
In the success message dialog box above, click Yes.
Next, the OpenCore installation process on the USB drive will begin. Click “Install to Disk” in the “Finished Building Your OpenCore Configuration” dialog box.
Select your USB drive.
Click on your USB drive. The OpenCore installation process on the USB drive will begin. It won’t take long.
Click Reboot.
Step 5: Installing macOS Monterey
From here, the macOS Monterey installation process will begin. After clicking the “Reboot” button, press and hold the Option key on your keyboard until the boot menu appears on your MacBook Pro.
Select EFI Boot.
Select “Install macOS Monterey.”
The Recovery page appears.
You have two installation options. The first is an installation that doesn’t erase your data, and the second is a full installation, which means you’ll have to erase all the data on your MacBook Pro. In this guide, I’ve chosen the full installation, so I’ll need to erase the data on my MacBook first.
1. Install Without Deleting Data
So, to install macOS Monterey without erasing your data, on the Recovery page, select “Install macOS Monterey.” Click the “Continue” button, and then on the page with the large macOS Monterey icon, click “Continue.”
Click “Agree”.
Click the “Agree” button again in the “I have read and agree to the terms of the software licence agreement” dialogue box.
Select your disk. Click Continue.
The installation process will now begin. Please wait until it is complete. This process will install macOS Monterey on your MacBook Pro without deleting any data.
2. Full Installation with All Data Deleted
If you plan to perform a full installation of macOS, you can erase the data on the hard drive. On the Recovery page, you can select Disk Utility and click Continue.
Select your hard drive.
Click the Erase button. Give it a new name or leave it as it was. Select the APFS format. Click Erase. Wait until the erasure process is complete, as indicated by the ‘Erase Process is Complete’ dialogue box. Click Done.
When you’re done, exit the Disk Utility page.
Then, on the Recovery main page, select ‘Install macOS Monterey’. Click ‘Continue’ and then click ‘Continue’ again on the macOS Monterey icon page.
Click ‘Agree’.
Click ‘Agree’ again in the dialogue box labelled ‘I have read and agree to the terms of the software licence agreement’.
Select your hard drive.
Click Continue.
The installation process will begin. All you need to do is wait until it’s finished. You don’t need to do anything else. During the process, your MacBook Pro will reboot several times. The Mac logo and a progress bar will appear. The final progress bar is the one that displays the percentage.
If it hasn’t appeared yet, just let your MacBook Pro reboot several times.
Step 6: Setting up macOS Monterey
After going through a few steps, I’ve finally reached the macOS Monterey setup process. At this stage, I’ll fill in the details and make various selections, such as choosing a country or region, connecting my MacBook Pro to Wi-Fi and creating an account
To enter the data, simply follow the on-screen instructions. It’s just like installing macOS as usual.
Once all the setup is complete, you’ll immediately see the macOS Monterey interface on your 2012 MacBook Pro.
Step 7: Final Preparations
These final preparations include making a few adjustments to OpenCore Legacy Patcher so that it boots from the internal hard drive. I will also configure it so that it boots automatically from the MacBook Pro’s internal hard drive rather than from a USB drive.
1. Installing OpenCore on a Hard Drive
Shortly after successfully completing the initial setup, an OpenCore dialogue box will appear on the desktop. Essentially, this dialogue box states that OpenCore is not yet available on the hard drive. If OpenCore is not installed on the hard drive, it will boot from the USB drive.
You surely don’t want to have to plug in a USB stick every time you boot up.
In that dialogue box, click the OK button.
The OpenCore installation process will then appear, just as it did when you first installed OpenCore on a USB drive. Click the ‘Install to Disk’ button.
Select the installation location on the hard drive.
Click ‘Volume on disk0’.
Click Reboot.
2. Configuring Boot From the Hard Disk
Immediately after clicking the ‘Reboot’ button, you can unplug your USB drive, then press and hold the Option key on your keyboard. The boot menu will then appear. Select ‘EFI Boot’. At the same time, press the Control key; the arrow will change to a circle, which will set ‘EFI Boot’ as the default boot option.
Your MacBook Pro will now boot from the hard drive. And here’s the result. macOS Monterey is now running on my MacBook Pro 2012.
After Installing macOS Monterey, I was Able to Install AnyDesk and TeamViewer
So my aim in installing macOS Monterey was so that I could install a remote desktop application.
This is because, on macOS Catalina, remote desktop applications such as AnyDesk and TeamViewer cannot be installed; when attempting to install them, a message appears stating that the applications can only be run on macOS 11. After upgrading to macOS Monterey or version 12, AnyDesk and TeamViewer can be installed and run normally. In addition, I was also able to try out CCTV camera applications that run on a Mac, which were previously not supported on macOS Catalina.
Final Thoughts
This is my experience of installing macOS Monterey on a 2012 MacBook Pro. The 2012 MacBook Pro is a model that is not officially supported for macOS Monterey. However, the OpenCore Legacy Patcher application allows users of Mac devices manufactured before 2012 to install newer versions of macOS. You can follow my guide; this is a guide I wrote in August 2026. Whilst writing this guide, I failed time and time again but eventually found the solution, which I’ve included directly in this guide.
I hope you find this guide useful. If you have any questions, please feel free to leave them in the comments section below.
