macOS 15 Sequoia was officially released in June 2024, but Apple dropped support for many devices manufactured before 2018, including my 2015 MacBook Pro, which lost support starting with macOS Monterey 12.7.6. But you know me — that’s not going to stop me! 😀
I managed to bypass this limitation using OpenCore Legacy Patcher (OCLP) and bring Sequoia’s new features to my old friend!
I followed this excellent YouTube video by Anson Alexander, which provides clear, step-by-step instructions for upgrading unsupported Macs using OCLP. The process was straightforward, and after the installation, my MacBook is running smoother than ever with the latest macOS features! 😀
Here are few extra tips based on my own experience that were not mentioned in the video:
- Use a High-Quality USB flash drive: OCLP performs intensive data copying when setting up the installer on the USB. If the drive quality is low, you might encounter errors during preparation. I’d recommend a reliable, high-speed USB-3 drive to avoid issues.
- Fixing the “The bless of the installer disk failed” Error: While setting up the USB flash drive, you might see an error like “The bless of the installer disk failed” with a message saying “You don’t have permission to save…” To resolve this, go to System Settings -> Privacy and Security -> Full Disk Access and grant full access to Terminal. This should fix the permission issue.
- Use a Download Manager for the macOS Installer: When creating the installer, it’s better not to download it directly. Instead, right-click and select Copy Link, then use a download manager to download the macOS installer. This can ensure a more reliable and faster download, especially if you face interruptions or slow speeds during the process.
- Required downgrade and upgrade path: Since I needed to perform a clean install, I had to first format my drive and reinstall macOS El Capitan, which was the original OS installed on my Mac. To upgrade to Sequoia, I then had to upgrade to macOS Sierra first because Sequoia requires at least Sierra to be installed. From there, I could upgrade to Sequoia. Another possible route is upgrading from El Capitan to Monterey first, and then to Sequoia.
- Future upgrades made easy: You only need to install one of these versions (Sierra or Monterey) using OCLP and the USB drive. After completing the post-installation process with OCLP and patching the system, you no longer need the USB drive again for future upgrades. From that point, you can simply download and run the installer for a newer macOS version, and the upgrade within your current macOS and it will proceed without issues. Just after upgrading to any new version, don’t forget to run the post-installation process again with OCLP.
- Be careful when formatting the Mac internal drive: During the clean install, be sure to format the partition, not delete it. Deleting the partition may cause issues with the installation, so formatting is the safer option.
If you want to give new life to your legacy Mac, check out the guide — this upgrade was absolutely worth it!