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lunarworks

Q: Mac won't wake from sleep sometimes, half of RAM subsesquently disappears

I have a Mid-2009 13" MacBook Pro, and in the last few months I've been encountering this problem.

I'll close the lid on it to put it to sleep, and later when I open the lid again it won't wake. Then I close the lid again, and the "sleep" light on the front pulsates, but when I open it, the sleep light turns off like it's supposed to but still nothing happens. Close lid again, sleep light comes back, open again, light goes away, nothing happens. So, I have no choice but to turn it off (press power button for a few seconds) and turn it back on again.

However, and this is something I just recently noticed because I wondered why my computer was being so sluggish: When I turn my Mac on again after this happens, it registers 1GB of RAM rather than 2GB that are installed. I can usually get the 2GB to reappear if I attempt to reset the SMC.

What should I do about this problem? Do you think it's a problem with the RAM or the motherboard? It still has the RAM that came with it. Should I take it to the Apple Store? (Mind you, this problem doesn't happen every day.)

MacBook Pro 13" - Mid-2009, Mac OS X (10.6.2)

Posted on Mar 26, 2010 10:33 AM

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Q: Mac won't wake from sleep sometimes, half of RAM subsesquently disappears

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  • by macprorocks,

    macprorocks macprorocks Mar 26, 2010 10:40 AM in response to lunarworks
    Level 2 (230 points)
    Mar 26, 2010 10:40 AM in response to lunarworks
    Try Resetting the SMC:
    Note: Portable computers that have a battery you should not remove on your own include MacBook Pro (Early 2009) and later, all models of MacBook Air, and MacBook (Late 2009).
    Shut down the computer.
    Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
    On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
    Release all the keys and the power button at the same time.
    Press the power button to turn on the computer.
    From: http://support.apple.com/kb/HT3964
  • by lunarworks,

    lunarworks lunarworks Mar 26, 2010 10:49 AM in response to macprorocks
    Level 1 (0 points)
    Mar 26, 2010 10:49 AM in response to macprorocks
    Doesn't seem to help. Half my RAM is still missing. (Hasn't reappeared yet, this time.)
  • by ~Bee,

    ~Bee ~Bee Mar 26, 2010 2:21 PM in response to lunarworks
    Level 7 (31,777 points)
    Mac OS X
    Mar 26, 2010 2:21 PM in response to lunarworks
    lunar --
    One stick of RAM is either dead or unseated.
    Open up Sys Profile > Memory. Does it tell you which stick is not operating well?
  • by lunarworks,

    lunarworks lunarworks Mar 26, 2010 2:53 PM in response to ~Bee
    Level 1 (0 points)
    Mar 26, 2010 2:53 PM in response to ~Bee
    It was Bank 1 that wasn't working earlier. But, I went out for a walk for a couple of hours, and when I came back just now my Mac wouldn't wake up... AGAIN. But now Bank 1 is working again.

    I'm gonna switch it over to Bank 0. That way, if this occurs again (which it will), I'll know it's that stick and not the motherboard.

    I found a good price on 2x2GB of RAM. I've been wanting to upgrade, anyway. Just have to wait and see which level of hardware it's a problem at.
  • by lunarworks,

    lunarworks lunarworks Mar 29, 2010 12:14 PM in response to lunarworks
    Level 1 (0 points)
    Mar 29, 2010 12:14 PM in response to lunarworks
    Well, I switched the memory. It's not a bad stick. Bank 1 appears empty, again.

    Gonna have to call Apple.
  • by ~Bee,

    ~Bee ~Bee Mar 29, 2010 7:21 PM in response to lunarworks
    Level 7 (31,777 points)
    Mac OS X
    Mar 29, 2010 7:21 PM in response to lunarworks
    Aw, shoot.
    But I'm glad you got in narrowed down really well.
    Keeping fingers crossed for you.
  • by atatistcheff99,

    atatistcheff99 atatistcheff99 Apr 26, 2010 9:11 PM in response to lunarworks
    Level 1 (0 points)
    Apr 26, 2010 9:11 PM in response to lunarworks
    I have this EXACT problem after taking my Macbook in to have a video problem fixed. Looks like they did this to me at the Apple shop. I'd be interested to find out if you got a resolution. It might help when I take it back to get re-repaired. Mine shows slot 1 empty even though I checked and both have 2GB DIMMs installed.

    Thanks!
    Alex
  • by musicman3320,

    musicman3320 musicman3320 Jul 18, 2010 12:07 PM in response to lunarworks
    Level 1 (0 points)
    Jul 18, 2010 12:07 PM in response to lunarworks
    I too have had the exact same problem. The not waking from sleep, closing the lid and seeing the front light on, and having to restart with the power button only to find one of the sticks of RAM is missing. System Profiler reports one of the two RAM slots being empty. I also have the stock 2x1gb RAM sticks installed.

    I have taken my MBP into the Apple Store twice now for this problem. The first time they replaced both sticks of ram and the logic board. The problem disappeared for about a week, and then it started again. I took it in again, and this time they told me one of the ram sticks appeared to be loose. They fixed that and restarting it a few times without reproducing the problem (though, since the problem is intermittent this does not mean it was fixed). Again, for about a week the problem disappeared, and then it returned.

    Have there been any updates on this? I do development with XCode on this machine, and it is very difficult to work efficiently with only 1gb of ram.