How to Downgrade OS X Yosemite Back to OS X Mavericks

For Mac users who have updated to OS X Yosemite and found it to be unbearable for whatever reason, you’ll be pleased to discover that downgrading back to OS X Mavericks may be a possibility for you. This is not specifically recommended, but if you’re absolutely set on reverting from Yosemite to the prior version of OS X running on your Mac, you can likely do so. We’re going to cover downgrading to Mavericks, but technically this process would work to get back to other versions of OS X too.

Be sure to read this thoroughly and understand what happens in this process, as it effects all files on the Mac and not just the OS X version: To downgrade back to OS X Mavericks from Yosemite, you absolutely must have a recent Time Machine backup made from OS X Mavericks – this is not optional using this specific technique. If you followed our preparation instructions or general good practice for system upgrades, you made a backup with Time Machine prior to updating to OS X Yosemite, so you’ll be good to go and be able to restore to the date of that last backup. That last part is important as well, because the date of the last Mavericks backup will represent what files and documents you get when you downgrade (For example, if you restore to a backup made on January 1, you’ll find files from January 1 and prior, and miss anything created between then and now, make sense?).

Be sure to manually copy any new files or important documents to another drive before attempting the downgrade process. This means any new files created under Yosemite in your user folders, Documents, Pictures, whatever, you should transfer to something like an external USB drive, another Mac, or network share. If you don’t do that, you will lose those files because you are essentially rolling back in time to a prior backup – that’s how Time Machine works. You can also just make a new backup before attempting the downgrade process, to another drive or whatever, and manually fish out the files, but that’s beyond the scope of this article.

Downgrading a Mac with OS X Yosemite Back to OS X Mavericks

You should start a backup of the Mac before beginning this process. Failure to backup may result in data loss or other unplanned problems. Don’t skip backups.

1. Reboot the Mac with Yosemite and hold down Command+R to enter Recovery mode (You can also hold Option and choose “Recovery HD”, or if you have a Yosemite USB installer key, you can boot from that too)
2. At the OS X Utilities menu, choose “Restore From Time Machine Backup”
3. Connect the Time Machine drive that contains the most recent Mavericks backup to the Mac (typically through USB or Thunderbolt), then click “Continue”
4. At the “Select a Backup Source” screen, choose the Time Machine volume used for the Mavericks backup and click Continue
5. Under “Backup Date & Time”, select the most recent backup made from OS X Mavericks – double-check the OS X Version menu to make sure it’s “10.9.5” (or whatever 10.9.x you had previously), then click Continue again
6. Choose the Destination drive (the Yosemite volume you want to downgrade) to restore the OS X Mavericks backup to – this will erase OS X Yosemite and revert back to Mavericks on that drive, be sure you backed up all files created between the most recent backup date and now or you will lose them – click on “Restore” to begin the downgrade process

This uses the restore function of the wonderful Time Machine backup solution to revert back to whatever version of OS X you had running in the most recent non-Yosemite backup made on that Mac. Because the backups from Time Machine are snapshots in time, you’ll likely want to make that decision sooner than later to avoid having to manually copy tons of new files, otherwise you risk losing them.

The downgrade process can take quite a while depending on the size of the backup, the amount of files on the drive, the speed of the Mac, and the speed of the hard drive. Expect this process to take several hours if not many hours, for a very large hard drive of stuff, it could easily take overnight if not a full day to complete hundreds of GB of file transfers. Do not interrupt the restore process, otherwise you would need to start over.

When the restore has finished, OS X Mavericks or OS X Mountain Lion will boot on the Mac, and you’ll have walked back in time away from OS X Yosemite.

At any point in the future you can always update to OS X Yosemite again if you decide to simply by either updating through the Mac App Store, with a USB installer drive, or even with a clean install.

Did you decide to downgrade your Mac from OS X Yosemite back to a prior version of OS X? Why or why not? Let us know your experiences in the comments.