You will therefore need to make a back up of anything you don’t want to lose. Most of the processes for reverting to an older version of macOS unfortunately mean you will need to wipe your Mac.

We have a separate article about installing a new macOS on an older Mac. This is because newer versions of macOS tend to drop support for older Macs. Similarly, if you were hoping to install newer version of macOS on an old Mac you might find that you can’t. If you are installing an old version of Mac OS X on an old Mac you shouldn’t have too many difficulties though. To help you find out what versions of macOS your Mac supports we have a full list of which Macs run each version of Mac OS X and macOS. However there may be exceptions, for example, if you bought a Mac in 2017, but the spec hadn’t changed from the predecessor, or the model was actually introduced a few years earlier, you may find you can run an older version of macOS on it. If you want to run older versions of OS X on your Mac, you need to get an older Mac that can run them. Simply speaking, Macs cannot boot into an OS X version older than the one they shipped with when new, even if it’s installed in a virtual machine. You may find you can’t install an old version of Mac OS X on a new Mac because the drivers for the hardware in your new Mac simply don’t exist in the old software, so it can’t run. Now for the bad news: It is unlikely that your Mac will be able to run a version of macOS or Mac OS X that is older than the one that was installed on it when you bought it.

First you need to confirm that your Mac will be able to run the version of macOS or Mac OS X you want to install.Īs a guide, expect your Mac to be able to run any version of macOS or Mac OS X that was supported when that Mac launched, and any that were released in the few years immediately following your purchase.

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