Reset Mac login password

Hello. Have you followed the steps in the KB here? Have you tried resetting your password with your Apple ID (if you have this option enabled)? Do you also know whether or not you have FileVault enabled? Whether or not you have FileVault enabled will impact the range of password reset options available to you.

I would suggest following the steps below if you haven't already to try resetting your password:

1. Restart your Mac and immediately hold down Command-R until you see the Apple logo or a spinning globe. 
2. When you see the macOS Utilities window, choose Utilities > Terminal from the menu bar.
3. In the Terminal window, type resetpassword, then press the return key to open the Reset Password assistant.
4. Select ”My password doesn't work when logging in,” then click Next and follow the onscreen instructions for your user account.

In addition to this, please ensure that you update your login keychain after resetting your password by following the steps at the end of the linked article. This will help to avoid any issues with your macOS keychain.

Hello. Thanks for the update. If recovery mode is not working, that makes things a little trickier. If you have a macOS High Sierra install USB, you could boot from this and use this to reset the administrator password. You need an administrator's password in order to create a recovery USB, however, so you may be unable to create a recovery USB without access to another Mac. Do you have any friends or family with Macs that can help you create a High Sierra USB recovery drive to get your administrator password reset?