I'm running MacOSX 10.5.8 on a MacBook Pro.

I was working on my computer last night. I finished work, closed the lid and expected the computer to go to sleep. I assume this is the Apple Safe Sleep mode. My battery was about 70% charged.

Tonight, I open up my laptop and discover that the computer refuses to start and battery has been completely discharged. When I plug the computer in again, all information from my previous session was lost. It's as if the computer shut down completely.

What's happening here? Shouldn't the computer go to sleep and save all information to disk? When I wake the computer up from sleep mode, shouldn't it restore all information from my previous session?

This only happens about 5% of the time that I close the lid. Usually, this works as I expected.

Update to answer @zneak's question:

This is the hardware model, according to About this Mac: More Info...: Hardware.

Model Name:       MacBook Pro
Model Identifier:   MacBookPro3,1
  • 2
    How old's your MacBook Pro?
    – zneak
    Commented Oct 11, 2010 at 5:03
  • @zneak : How do I tell? I did not purchase this computer, it's a work computer (I could ask our admin, but he's out today). Commented Oct 11, 2010 at 17:19
  • You can tell by opening the Apple menu and clicking "About this Mac". Then, click the "More infos" button. Click the "Hardware" element in the left tab. There, you'll find the Model Identifier, which is what we need. (For instance, my current-gen MacBook Pro is a MacBookPro6,2.)
    – zneak
    Commented Oct 11, 2010 at 17:23
  • @zneak : I updated my question with the information. Commented Oct 11, 2010 at 17:36

1 Answer 1


What happened could’ve been because of different reasons. Certain old Macbook Pros had troubles with sleeping (hence why zneak wants to know about the model).

However I believe that your computer woke up (wake on lan? hung process?) during the night and it burned through your battery. What are your Energy Settings?

Also, get some sort of CPU meter like MenuMeters or iStats Menu (€) and make sure your CPU/Cores are not 100%, that indicates a process that’s using all your CPU power (and a lot of energy!)

  • -1. Menubar monitors won't help if you have the lid shut. Best you can do is check before you shut the lid.
    – Josh K
    Commented Oct 11, 2010 at 10:15
  • 1
    @Josh I believe that’s obvious, isn’t it? Or are you going to use your computer with your lid closed and no external display/keyboard connected? What’s your point? OF COURSE it’s for when the computer is on and open. A process is not going to spawn in the middle of the night for no apparent reason. Unless he has poltergeists. Be serious please. Commented Oct 11, 2010 at 22:31
  • 1
    There are programs / utilities that will wake your computer and burn battery life. That's why it's best to shut it down instead of sleeping if you aren't simply moving to another location.
    – Josh K
    Commented Oct 11, 2010 at 22:41
  • 2
    @Josh best to shutdown? That doesn’t make any sense. If you are moving to another location, you might consider shutting down (if it’s going to take more than one day) but other than that, sleeping is almost always better. Who shuts down a Mac, especially a Macbook/Pro! I rarely shutdown a Mac Pro. Sleep is always better unless you really need the battery as charged as possible. Sleep can last for a few days. Commented Oct 12, 2010 at 3:40

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