OS X El Capitan: If your administrator password was not accepted
Make sure you entered your password correctly
If you enter the administrator password for your Mac and get a message that the password you entered is incorrect, there are a few things to try.
Make sure the password you’re using is correct.
Make sure you use the same capitalization you used when you created the password. Passwords in OS X are case-sensitive, and you need to enter them exactly as they were created.
If you still can’t remember the administrator password, you may be able to reset it. For more information, see If you forget your login password.
Last Modified: Apr 13, 2016