This is a hidden partition on your boot drive introduced with OS X 10.7 Lion, so the technique I'll describe works with OS X 10.7 Lion, 10.8 Mountain Lion, OS X 10.9 Mavericks and OS X 10.10 Yosemite.

If the techniques above aren't available, a very neat, simple way to reset the administrator password is to make use of the OS X Recovery Partition. If you can't do that, on to the next technique. If you've previously set up your Mac with two administrator accounts, highly recommended, you can use the second admin account to login in and reset the password for the first administrator whose password has been forgotten. One administrator has the power to reset the password of another administrator. If, heaven forbid, Apple's system is hacked, your admin password could be compromised. On to the next technique. One reason to deselect the box is extreme security.

However, if you deselected that box, and later forgot your password, you're out of luck. Enter your Apple ID and password, then click 'Reset Password' to proceed. Click the arrow-in-a-circle icon to bring up the 'Reset Password' dialog. If you incorrectly enter your account password at the login window three times, a message appears stating 'If you forgot your password, you can reset it using your Apple ID'. Now, assuming you've forgotten your password, according to Apple.

If you did that, the box in System Preferences > Users & Groups was set. When you first set up your Mac or upgraded the OS, The Setup Assistant will ask if you want to allow your Apple ID to reset the user (admin) password. For the sake of completeness, I'll reference those methods at the end of this article. Some of them are rather Unix-geeky and can make a novice user nervous. To be clear, there are several technical ways to reset the administrator password on a Mac. Nowadays, there is no install disc provided with OS X, and so an alternative method is necessary. If a user forgot the administrator password, perhaps the simplest way (of several) would be to use that disc to set a new administrator password and regain control of the Mac. In the early years of OS X, the Mac operating system was sold on a DVD.

Macos reset admin password