Recovery Mode will allow you to change your password.
You'll need to boot your Mac into Recovery Mode in order to access the password reset tool. I've found the easiest way to do that is to start by completely powering down your Mac.
From there, the process to getting into Recovery Mode will depend on the kind of Mac you have. For Macs with an Intel processor, press and hold the Command and R keys on your keyboard, then press the power button. Hold Command+R until you see a progress bar show up below the Apple logo. You can also get into Recovery Mode by restarting your Mac and trying to time the keyboard combo of Command+R, but in my experience, starting with your Mac turned off is the most reliable method.
For the recently released Macbook Air, MacBook Pro and Mac Mini that use Apple's M1 processor, you'll need to turn off the computer and then press and hold the power button until you're presented with an options button. Click it and then select Recovery. (We have a more thorough walkthrough of Recovery Mode on the M1 Macs.)
With your Mac now in Recovery Mode, click on Utilities in the menu bar followed by Terminal. A new window will show up, waiting for you to enter a command. Type "resetpassword" as one word, without the quotes, and press Return.
Close the Terminal window, where you will then find the Reset Password tool. Follow the prompts, which include signing in with your Apple ID and then selecting the user account you need to change the password for.
Recovery Mode will allow you to change your password.
You'll need to boot your Mac into Recovery Mode in order to access the password reset tool. I've found the easiest way to do that is to start by completely powering down your Mac.
From there, the process to getting into Recovery Mode will depend on the kind of Mac you have. For Macs with an Intel processor, press and hold the Command and R keys on your keyboard, then press the power button. Hold Command+R until you see a progress bar show up below the Apple logo. You can also get into Recovery Mode by restarting your Mac and trying to time the keyboard combo of Command+R, but in my experience, starting with your Mac turned off is the most reliable method.
For the recently released Macbook Air, MacBook Pro and Mac Mini that use Apple's M1 processor, you'll need to turn off the computer and then press and hold the power button until you're presented with an options button. Click it and then select Recovery. (We have a more thorough walkthrough of Recovery Mode on the M1 Macs.)
With your Mac now in Recovery Mode, click on Utilities in the menu bar followed by Terminal. A new window will show up, waiting for you to enter a command. Type "resetpassword" as one word, without the quotes, and press Return.
Close the Terminal window, where you will then find the Reset Password tool. Follow the prompts, which include signing in with your Apple ID and then selecting the user account you need to change the password for.