Reset Administrator password on my Macbook Air

Determine if the following method will work for you:

1. Shut down your Mac and turn it back on while holding down the ⌘ and S keys at the same time until your see a black screen with white text. This is known as Single User mode.
2. You can skip the next step, but it is recommended that you do not because it will check your boot volume for errors and correct what it can:

   At the :/ root# prompt, type fsck -fy and press Return or Enter. It will take a few moments to complete. If you are concerned that nothing is happening just press the Return key until you see the :/ root# prompt again. Once the disk check is complete and the prompt returns, type mount -uw / and press Return / Enter.

3. Type launchctl load /System/Library/LaunchDaemons/com.apple.opendirectoryd.plist and press Enter.

   If you get an error message you may ignore it.

4. Type ls /Users and press Enter. All of the usernames on the computer will be listed, which is helpful if you don’t know or remember what these are.
5. Type dscl . passwd /Users/username password while replacing username with one of the users displayed in the previous step and replacing password with the new password of your choice. Press Enter. You will likely get an error message about a file or directory not being found. You may ignore this.
6. Type reboot and press Enter.