OS X Yosemite
Revert to a previous OS X version
Reprinted from
at
https://support.apple.com/kb/PH18846?locale=en_US
If you use Time
Machine to back up your Mac, you can easily revert
to a previous version of OS X if you experience trouble
after installing an update.
Important: Reverting
erases any changes you made to the
files on your Mac since you
installed the new version of OS X.
To save new or revised files, copy
them onto a different disk or back
them up before you follow these
instructions.
-
Print these
instructions: Click the Share button
in the Help window, then choose Print.
-
Choose Apple menu >
Restart. After your Mac restarts and you
hear the startup chime, hold down the
Command (
) and R keys. When the Apple
logo appears, you can release the keys.
-
Select “Restore from
a Time Machine Backup,” then click
Continue.
-
Select your Time Machine
backup disk.
-
Select the Time Machine
backup you want to restore. To restore
your computer to the state it was in
before you installed the new version of
OS X, choose the most recent backup that
occurred prior to installing OS X
Yosemite.
-
Follow the onscreen
instructions.
If you backed up files as
described in the Important message above,
you can restore them now. If you backed them
up using Time Machine, click the Time
Machine icon
in the
menu bar, choose "Enter Time Machine",
then retrieve your files.
Recover your entire system
Click here for Apple's
instructions to
Recover Your Entire System.
Last Modified: Mar 4, 2015