I've got a MacBook Pro protected with FileVault 2 (10.9), and can't remember the password to unlock the disk.
When I boot, it asks for the "Disk Password".
What I have is the recovery key that I printed on paper when I activated FileVault.
How do I use it ?
Entering a wrong password multiple times doesn't prompt for the recovery key, and sometimes a '?' appears but it doesn't do anything.
(I've read http://support.apple.com/kb/ht4790, but it doesn't explain how to use the recovery key.)
Best Answer
Use the recovery key to reset the login password
Retrieve the recovery key you copied down when you turned on FileVault disk encryption.
If you cannot find your recovery key, but stored it with Apple, contact Apple Support.
Restart the computer. On the login screen, click on the account to unlock and reset the login password.
In the password field, click on the Question Mark (?)
If you created a password hint, it is displayed.
If you remember your password then enter it now.
If you still need to reset your password, click the bottom line “reset it using your Recovery Key,” and then enter your recovery key.
Alternative method:
Recovery
If a user forgets their password, and a recovery key was installed before FileVault 2 was turned on, you can use the following steps to unlock an encrypted disk. Note: This procedure only works when the computer is started from OS X Recovery.