What causes hibernatemode to switch?

Discussion in 'MacBook Pro' started by mrkgoo, Mar 10, 2010.

  1. mrkgoo macrumors 65816

    Aug 18, 2005
    Ok, I was always used to my old PowerBook fast sleep (without writing a sleepimage), so when I got my early 2008 MBP (non-unibody), I set the hibernatemode to 0 (default for new MacBooks is 3, which writes out a sleepimage file to HD, the size of your RAM).

    So this has been fine for a couple years, but on March 4, it changed back to 3.

    Does anyone know what causes this random reversion of hibernatemode?

    I've recently upgraded my HD and my RAM, so maybe that did it (I actually changed my RAM on March 2, and tested it on March 3), but was just curious if anyone had more insight.

    Since I have a large amount of free space, I might just leave it in 3.
  2. jkozlow3 macrumors 6502a

    Jul 16, 2008

    Same thing happened to me recently when I noticed my hard drive free space was shy by about 4GB (the amount of ram I have). In my case it was immediately after installing VMWare Fusion and rebooting. I then set the sleep mode back to 0 and regained 4GB of disk space on my 80GB SSD.
  3. jkozlow3 macrumors 6502a

    Jul 16, 2008
    FYI, I just noticed a 4GB drop in free space again and found the culprit.

    Clicking "restore defaults" inside OS X's energy saver settings sets it back to hibernate. I verified this by repeating these steps while keeping a finder window open (displaying drive free space) and the 4GB free space drop was instantaneous. Restoring the defaults also turned the sudden motion sensor (SMS) back on (which I had turned off since I have an SSD).

    So now I'm not sure if my VMware Fusion installation was the previously the culprit or not. I very well may have done something in the energy settings around the same time I installed Fusion. Who knows.

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