iMac with Lion not waking after overnight sleep

I have two iMac (with Lion), they only connect to Ethernet, no WiFi, only one iMac has this problem. When it cannot wake up, I connect a USB mouse and the screen comes back. From 'System Preferences', when click Network & Bluetooth, no response. I need to "force to quit" them. Then I select "Shut Down" from the menu, the screen changes to grey screen, small cycle icon is running in the middle of screen and the system never shut down. Finally, I need to press the Power button for 4 sec to reboot it.

From my experience with other Linux systems, when the lower level devices such as Network is not responding, the system freezes same as this case. From my simple mind, I think when the system in the sleep mode, some processes detach the device driver(s) from the kernel process list, so system does not response to any Bluetooth devices.

This is a very difficult to reproduce problem, but Apple should fix it.

I'ave had this problem with my iMac as well, but I don't let my machine sleep - I only let the displays sleep - and I've been able to wake it with a key press - but I'm using a bluetooth Logitech DiNovo Edge and not the Apple bluetooth keyboard.

I also had my screensaver set to Word of the Day and so based on earlier comments about the screensaver possibly flubbing it up, I changed it to Arabesque and now I can wake the screen from sleep without any issues with the mouse.

Weird, but simple solution.

Now with Lion 10.7.2 I still have the same issue. Apple, please!!!

I have this issue as well:

iMac 11,3 (2010 27", i7 chip) with bluetooth Apple keyboard, trackpad, magic mouse: this problem NEVER happens, before or after Lion upgrade. Never.

iMac 9,1 (2009 24", Core 2 Duo chip) with SAME models bluetooth Apple keyboard, trackpad, magic mouse: this problem happens FREQUENTLY, starting AFTER I upgraded to Lion, and persists with Lion 10.7.2. It happens upon waking from a long, not short, sleep. In System Preferences I have computer sleep at 1 hr, display sleep at 30 min, no screensaver ever, Ethernet on (I have a wire to my Apple extreme), Airport off. I have a bunch of USB devices connected to two powered USB hubs, and two Firewire drives.

I am coming to this thread for the first time tonight and will try some of the solutions offered.

Question: if one sets Energy Saver so that the computer NEVER sleeps, does the problem go away?

New behavior, after my iMac wake up, the mouse and keyboard are OK this time, but the network is not working. I can use the ping command to ping yahoo.com and apple.com from the Terminal, but none of the GUI application can connect to internet. I switched to DHCP or manual IP mode, use ethernet or/and WiFi, same problem: can ping but GUI app does not work. After reboot, the GUI app can access network.

Wow!! I did the very same thing today (unpairing trackpad) hoping it was the culprit. Will test it tonight!!

Question: if one sets Energy Saver so that the computer NEVER sleeps, does the problem go away?

I have the "never sleep" option, but still got a BSOD this morning when I oened the lid of my MBP. I also got a new dialoguw to enter a password for iTunes to give me automaic updates. Maybe this is relevant, maybe not.

I've sent a BR to Apple.

I have the same machines and problem as stevewhitemd. My iMac 2010 i7 never has the problem before and after upgrade to Lion. My iMac 2009 Core 2 Due has this problem after it is upgraded to Lion.

Does you think Apple support Eng read this thread? Does Apple publicly address this problem?

So first step: I unpaired and turned off my Apple Bluetooth trackpad.

That was it.

Overnight and today: no disruptions whatsoever. Everytime the iMac woke up from deep sleep it woke up perfectly.

I still have the Magic Mouse and shortie keyboard in the Bluetooth chain.

I realize others have tried this without success. I am wondering: is it something about the number of Bluetooth devices one has?

I see SimonYeun1999's note. Perhaps it's the Core 2 Duo, but I've seen other posts in this thread from people with i3/i5/i7 iMacs with this problem.

definetly is the trackpad and 10.7.2 did not fix the problem!!

Four days now with the trackpad off, and with the keyboard and magic mouse on: still no problem.

I'm really beginning to think it's the trackpad.

Apple, if you're reading, please check the trackpad firmware with Lion again, I think you have a problem with sleep issues.

Concur!! I've had no problems since I unpaired my trackpad. Am considering re-pairing to see what happens.

I can only say when I disconnected my trackpad - the problem disappeared. A few days ago I plugged it back in in order to test 10.7.2 and my machine wouldnt wake up this morning.. So this problem is not fixed in 10.7.2.

I also suspect faulty trackpad firmware or something similair corrupting something..

This morning I plugged in a USB keyboard and did a PRAM reset as it turns out my bluetooth keyboard wasnt doing this properly. Will see...

My problem disappeared after that latest OS upgrade. Try deleting the BT devices and add them back.

Same for me: no more problem. I updated to 10.7.2 on both iMac 2010 i7 and iMac 2009 Core 2 Due last Sunday. The trackpad is also ON, the keyboard and mouse configuration are not changed. And, this problem is not happening on iMac 2009 Core 2 Due anymore. Let wait for few more days, I will post my status later.