authenticate user

This normally requires an administrator password (not Apple ID). If you are the sole user and administrator, this will be your login password (not Apple ID)

I am the sole user and administrator. I have repeatedly tried to use my user password--I used it to log into my MacBook to start this session and had to use it to access this forum so I know it works--but it will not unlock my MacBook to install the latest update. Any further suggestions?