iMac asks for password after power failure even no password has been assigned

You can choose not to have a login password under Privacy & Security/ General. While setting up a new iMac for a friend (who has never had a Mac) I didn’t want to have to keep putting in a password every time the computer went to sleep so I selected no password. When powering back up after the power failed during a storm, it asked for a password. When I enter blank for the password it doesn’t accept it. After about a half hour it did accept no password. I don’t know why.

I’ve done that and lengthened the time before it puts itself to sleep but it doesn’t answer the question why would it ask for a password when one is not set and then decide a half hour later it doesn’t need a password after all. It’s not a big problem but I just don’t like unanswered questions. Thanks for your help.

It wasn’t a wake from sleep or stall and there wasn’t any wait time.

It shut down because of a power failure. When the power was back on, the computer was powered up and immediately asked for a password even though it is configured with no password.

To check if it was just a freak one time thing, I unplugged it from the wall to simulate a power failure. When I plugged it back in and powered it up the same thing happened - it expected a password and would not accept a blank entry. After hitting enter with a blank password space every few minutes for about a half half hour it finally accepted a blank password.

It’s not a big problem but seems strange and unexpected behavior with no logical explanation which is always a bit worrisome.

It works fine with a simple password.

Thanks for your help.