You need to note that you will lose all of your data no matter what downgrade method you choose. So ensure you have a backup from your last OS, i.e., macOS Sonoma. When you followed the macOS 15 installation guide, you must have been advised to create a full Time Machine backup to an external hard drive. If you have new data created after you installed macOS Sequoia or you don’t have a backup from previous OS, you need to copy files manually and avoid taking a full Time Machine backup; otherwise it will also backup the macOS Sequoia system. With all of that sorted out, let’s jump to the downgrade methods.
Downgrade macOS 15 Sequoia using macOS Recovery
If you have a Time Machine backup from your last OS, then the easiest method to downgrade is using that backup. The method for Time Machine backups works on the basis that you have an external drive to which you backed up your data before installing the macOS 15 Sequoia. This is generally useful for those who might be having a lot of data that could be important. You can follow these steps to downgrade or restore your macOS. During the setup, you will also get option to restore backup. Use the on-screen instruction to get back data.
Downgrade from macOS Sequoia via Bootable Installer
This method requires a bootable USB drive of the macOS version that you want to install (in this case macOS Sonoma). Also keep the drive that has your Mac backup to restore your data later. Here are the steps to create a bootable USB drive.
Create a Bootable USB Drive
Roll Back using the Bootable USB Drive
Now that you have created the bootable drive, here is how you can use it to downgrade your macOS. You will also get option to restore your backup. Follow the on screen instructions and your data will be restored. If you have files backup, you can copy them later. This concludes the guide to downgrade macOS 15 Sequoia to macOS 14 Sonoma. Yes, the process might feel a bit complicated, but there are no other options. Do remember to always keep a backup of your data whenever you plan to upgrade or downgrade your Mac’s OS. Personally, the Time Machine method is the best when it comes to creating and restoring backups, as it automatically backs up all your important data. Also Check:
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