Apple’s release of Yosemite has brought with it the ability to use an Apple ID to unlock and reset a forgotten account password to log into a FileVault 2-encrypted Mac. You can use this ability in a couple of ways:
1. By setting up your iCloud account as your account on the Mac in question.
2. By associating your local or mobile network account on the Mac with an Apple ID, and selecting the option when enabling FileVault 2 to use your Apple ID to unlock the disk and reset your password.
Note: This method uses Apple’s services to store the needed FileVault 2 recovery key. If your Mac’s FileVault 2 recovery key is not being stored by Apple, you will not be able to use an Apple ID to reset your account’s ability to log into a FileVault 2-encrypted Mac.
For more details, see below the jump.
Here’s the procedure for resetting a forgotten account password using an account’s previously-registered Apple ID.
1. At the FileVault 2 pre-boot login screen, select the account in question.
2. Click on the question mark icon.
3. In the options displayed, click on the …reset it using your Apple ID option.
4. The Mac will reboot to your Mac’s recovery partition and access a Reset Password wizard.
5. When prompted, log in with your account’s associated Apple ID.
6. Depending on what type of account you have, the next few screens may be slightly different.
iCloud account
A. The Reset Password wizard will check the locked disk
B. The Mac will communicate back with Apple to match the iCloud user against the FileVault 2 recovery key that was stored with Apple.
C. The iCloud account will be re-enabled for FileVault 2
D. You’ll be prompted to restart. On login, your iCloud account password will be able to log in at the FileVault 2 pre-boot login screen.
Local or Mobile Network Account that’s associated with an Apple ID
A. The Reset Password wizard will check the locked disk.
B. The Mac will communicate back with Apple to match the Apple ID against the FileVault 2 recovery key that was stored with Apple.
C. You’ll be prompted to reset your account’s password to a new one.
Note: This may break the password sync for a mobile network account between the network account’s cached password on the Mac and the directory service.
D. You’ll be prompted to restart. On login, your now-reset account password will be able to log in at the FileVault 2 pre-boot login screen.
