Ouch, the Filevault/Master Password is totally different.
One of the drawbacks of encrypting data is that if the user forgets his or her password, access to the files in the home folder is lost. If an account has FileVault enabled, an administrator user cannot use Accounts preferences to change that account's password, nor can the administrator user turn off FileVault for the account; only the user can do that.
Because users often forget passwords, Mac OS X provides a master password feature to allow passwords on FileVault-protected accounts to be reset. The master password is used only as a back door for recovering FileVault-encrypted accounts. If during login a user enters three incorrect passwords for his or her FileVault-encrypted account, the account's password hint is displayed along with a Reset Password button. After the user clicks Reset Password and enters the master password (obtained from the administrator), he or she can set a new login password.
If you forget the master password, you can reset it, but you must know the passwords for any accounts with FileVault enabled:
- As an administrator user, delete the master password keychain file (/Library/Keychains/FileVaultMaster.keychain). When the master password keychain is deleted, Mac OS X assumes that no master password is set yet.
- In Security preferences, set a new master password.
- Log in to each account that has FileVault turned on, and use Accounts preferences to reset the password for each account.
Do not forget the master password! Although it is possible to reset the master password, it still requires all users with FileVault-protected accounts to know their passwords. If a user has forgotten his or her login password, and you have forgotten the master password, there is no way to recover the user's data.