I got a new computer today. I my parents logged in with a username I didn't want so I made another admin. Now, I'm trying to delete the old account.
when I go to Users & Groups in System preferences, click on the old account, hit the – sign to delete it and enter the password, the popup shakes like the password didn't work. I'm sure the password is correct because I used it multiple times to log into the account. I tried switching the old account to admin but that didn't work.
Best Answer
If you can't delete the user for some reason, you can remove it at the command line.
Launch "Terminal" (from /Applications/Utilities/Terminal.app, or search via Spotlight) and type:
...followed by your administrator password. Then hit enter
The output will show you the shortname of your local users (towards the bottom). Here I called the user to be removed "testy" (I'm only showing the last few entries):
Now remove the user from your system and from System Preferences (exchanging the shortname "testy" with your own, found earlier):
Then hit enter.
The home folder of that user you can either keep, if there are important files, or delete it with...
...and again hit enter.
PS. A speculative answer for the permissions error received and mentioned in the comments section can be found at StackExchange: What causes eDSPermissionError when running dscl?