Resolved Ok, macOS Monterey doesn't know me...

[I WAS the one]

I get the upgrade notification but a window asking for my admin password is showing up saying I can't upgrade because my admin password is not working. I'm the only user, the only password I have since day one, and now I can't use it to upgrade the OS! Can someone explain this to me??

 

[Taz Mangus]

I get the upgrade notification but a window asking for my admin password is showing up saying I can't upgrade because my admin password is not working. I'm the only user, the only password I have since day one, and now I can't use it to upgrade the OS! Can someone explain this to me??

Try booting int Safe Mode and then back to normal mode. Then try Software Update.

 

[I WAS the one]

Problem solved. I went to Apple Store, They literally right-clicked on the user access window (where you put your password to start using your Mac) select reset password, change the password and everything was fixed. I'm not joking.