When you say it goes into Sleep Mode, does the LED pulse or is it continually lit? If the LED stays lit, then it is just your screen backlighting that is off, you're not actually in Sleep Mode.
If it does pulse, try setting the battery and power adapter settings to Never and see if you're still having this issue.
I didn't realise that the light stayed on when the screen has switched off - that's new behaviour. Thanks!
However, it still goes too sleep to early (even with both sleep and display blanking set to never), but I've managed to correct it somehow. I simply turned off 'Put hard disk to sleep when possible'. As soon as I did that then I got the behaviour I was expecting.
Thinking that the hard disk sleeping behaviour had also changed (ie. that now it's supposed to also blank the screen, which would be odd), I turned the drive sleeping back on...and I still get the behaviour I expect!
I can only guess that unchecking and checking that option has reset something - maybe the settings I migrated from the iBook didn't quite correspond with how the Macbook works?
Anyway, thanks for the suggestions guys.
A number of sleep-related issues can appear after incremental Mac OSX updates, including the inability to properly go to sleep, problems waking from sleep, and having your display go to sleep without your Mac going to sleep. The most common culprit is Bluetooth. Try these tips to fix your sleep problems.
In System Preferences>Bluetooth, uncheck Allow Bluetooth Devices To Wake This Computer. If you are using a Bluetooth mouse and keyboard, you'll have to wake your Mac by pressing the power button.
Your Bluetooth preference file may be corrupt-you'll need to delete it. Turn Bluetooth off, then go to the /Users/user name/Library/Preferences folder. Look for a file called com.apple.Bluetooth.plist and trash it.The OS will create a new preference file when you enable Bluetooth again.
If you have issues with a Mac or display that goes to sleep at inappropriate times, you may have a problem with Energy Saver. Delete the following .plist files and restart:
-/Users/username/Library/Preferences/com.apple.systemuiserver.plist--(username is your name or System Administrators name).
A restart is very important after deleting these plists. After a reboot your Mac will then generate new ones.
Some, in these forums, have had luck fixing sleep issues downloading the Combo update from this site (yours may be corrupt), not Software Update, disconnect all firewire + USB devices except keyboard + mouse, Repair Permissions, re-install update, Repair Permissions again + try.
Yours would be the 10.4.6 Intel Combo update. Others reading, download the combo update that applies to you!
because i wasnt having any luck with my own problem as a "shutdown" issue (which i still believe it to be. the light goes off but comes on when the laptop is closed after going dark) i attempted to follow the steps above.
im wondering what it means that i dont have the last 2 of those preferences listed.
I have a similar issue but not quite the same. When my Macbook goes to sleep after closing the clamshell lid, once a full sleep kicks in after 15 mins, I lift the lid and the machine works fine for a few mins then switches itsself off. If you press the power button it comes back on but then after a min or two goes off again. This is plugged in or unplugged. The battery is fully charged. The only was to get it to stop happening is to hold the power key down until the sleep light at the front flashes fast and it restarts. Then it is fine until the next time you sleep. I did try deleting the plist file but this has not solved. Any ideas?
I'm having the EXACT same problem. I'll put my MacBook to sleep by closing the lid and then wake it up by opening the lid later in the day. I'll be using the computer and it'll work for about two minute then the screen will go black and the light on the front will light up but not pulse. It won't wake up from hitting the keyboard, mouse or AppleControlPower. The computer is plugged in and fully charged. In fact, I have not been able to force restart my computer since I've had it. Every time I hit Apple Control Power my computer freezes and becomes unresponsive.
MacBook 2.0 Mac OS X (10.4.7)