I updated my MacBookPro and it won't close because system settings is open!

Sounds like you have to force a shut down.

Press and hold the power button until the Mac shuts down. Then restart again and see if the problem has cleared.

maryfromedina wrote:

I had a new download on my MacBrookPro and the "icon" for system settings will not go away, so I cannot log out.

You can force quit a shutdown by holding the power button/TouchID for ~6-10 sec.

Force Shut down your Mac.

Log out, sleep, wake, restart or shut down your Mac

Shut down or restart your Mac - Apple Support

reboot as normal and compare your results