Like the title says, I was trying to change my username on my MacBook (running High Sierra Version 10.13.6), it removed my admin privileges so I do not have an Admin account.
I tried rebooting in command mode and deleting the applesetupdone file, but it says the file does not exist, and when I reboot does not allow me to set up a new admin account, following the steps below:
Boot into Single User Mode: Start/restart your Mac. As soon as you hear the startup tone, press and hold ⌘ + S until you see a black screen with white lettering. (If you end up back on the login screen after a flash of the black screen with white lettering, enter your password and it will return to the black screen.)
Mount the drive by typing /sbin/mount -uw / then ↩ enter.
Remove the Apple Setup Done file by typing rm /var/db/.AppleSetupDone then ↩ enter.
Reboot by typing reboot then ↩ enter.
Complete the setup process, creating a new admin account.
What else can I try or do from here? Googling isn't giving me any options if the above doesn't work. Thank you!