Q: iMac won't sleep when press power button after update to 10.9.2

Not normal

2. Reset SMC.     http://support.apple.com/kb/HT3964

    Choose the right method.

Me too! No sleep when clicking the Power Button.

I wonder if this is one of those bugs that shows up soon after Apple updates the System.

Anyone else?

It seems that this is intentional. It will still work, but now you have to click and hold the power button for a few seconds and release it before it does a hardware shutdown. It is discussed here:

https://discussions.apple.com/message/24997352#24997352

Same problem here with my iMac !

Apple modified the behaviour of the power button in the OS X 10.9.2 update. To sleep the Mac now you must hold the button for about a half second, vs. a momentary tap in the past. It works the same way on desktops and portables.

The change may have been intended to placate those who didn't like its previous behaviour. For a couple of representative complaints read:

after installing maverick power button does not provide options to sleep, shut-down

New Macbook pro/air keyboard layout FAIL. 1000+ order on hold.

... etc.

Thank you ! The SMC reset does the trick.

I'm sorry Apple, but this is a very bad change.

Overloading the same button so that 4 (4!!!!) different duration keypresses have wildly different behavior is just not good interface design.

Do you think you can add a 5th behavior for the gap between 3-4 seconds? What are you guys thinking??

Same here but I found out that if you hold it for like .5 seconds longer and release it, it would shut down.