Unable to log out of user profile/shutdown/restart in OSX 10.11

I'm having this issue attempting to login on 2010 13" MacBook pro

did you hard reset by holding the power button? Do you see the beachball/pinwheel icon? Try signing in via a different user account (google how to create a new admin account from single user mode if you don't have one or know how to create one) then sign into that admin account and do the following:

Disable wifi

Delete the files in the folder /Users/<YOUR REAL USER ACCOUNT>/Library/Application Support/iCloud/Accounts/

Reboot

Log in to your normal account

If this works, thanks go to user Max108 https://forums.developer.apple.com/people/Max108

No go. No spinning wheel etc. Just mouse and desktop background. Must force shutdown using power button to reboot. I set up a second account with same results.

It seems the power button is getting a lot of use in 10.11B1 so far. Restart rarely works.

This is a bigger problem now as I cannot update to 10.11B2. The restart function will not work. It hangs indefinately. Only holding the power button and the sudo shutdown command work.

I figured it out. Reset the SMC.

Having this issue as well ever since B1, and still have it in B4 on a 2012 MacBook Air. Unoruantely neither resetting the SMC or zapping PRAM fully resolve it. i tried MalevolentPanda's solution (thanks for posting), which allowed me to reboot once, but after logging back into iCloud, the problem returned 😟

Any more ideas?