[Dell Switcher]

My iMac is about 4 months old and about twice a month after sleeping overnight the computer will not wake up. After several attempts pressing keys on the keyboard and clicking on the mouse, I have to unplug the Mac and then press the start button on the back and all is well!

Any other way to wake-up the Mac?

And do I have a problem or is this normal?

Thanks

[ghporter]

Not normal at all. Time for a trip to the Apple Store.

[Sherman Homan]

Do you have a wireless mouse/keyboard? I have seen them not wake a sleeping Mac.
Does it go into sleep/wake mode by pressing the button on the back? Check your Energy Saver in System Preferences, make sure the "Allow power button to sleep computer" is checked.

[Dell Switcher]

I do have wireless mouse...logitech bluetooth and I wonder if that is problem. But, the keyboard is USB connected. But, whenever I reboot, the Mac takes time to recognize the bluetooth mouse.

The Mac goes to sleep based on timing in my Energy Saver settings of 45 minutes.

[Sherman Homan]

Oh well, like ghporter suggested, it is off the the Apple store. A short delay (couple of seconds) with the wireless mouse is normal, but with a cabled USB keyboard it shouldn't behave like that.