I am running Maverick 10.9.5 on a MacBook Pro (2.4 GHz Intel Core i5). I can no-longer make any system updates as my admin name/password are not accepted. I only have one active user and I use the password to log on every time I use the laptop, so I know the password is correct. I have tried the user name listed in Users & Groups which is the current user and is classified as "Standard". The only other user listed is "Guest" which is "Off". I have also tried using the user name at ~/. Users and Groups is locked. I used to be able to make system changes because I was only prompted for the password, the user being supplied automatically (this may have been on an older version of the OS). I have heard of a bug where the administrator name was changed to "root", but that does not work either. Any suggestions? Thanks.