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I notice this pattern with my Macbook Pro anytime the battery reaches 0%. (Usually a result of me leaving it unplugged with the lid open).

  1. I plug it in
  2. No response, no way to make it start for around 5-10 minutes
  3. Eventually pushing the button turns it on
  4. Very slow start up...long pauses with either the beach ball or other waiting cursors.
  5. Even after the system starts up and I log in, it's really sluggish for perhaps 10-20 minutes, then eventually is normal.

So, my three questions:

  1. Is this normal? (This is my work machine - it's a few years old, I've been using it less than 12 months)
  2. If so, what causes each of the steps above? (For my education...)
  3. Is there anything I can do to improve it?

It's a 2.66Ghz Intel Core 2 Duo, Snow Leopard.

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possible duplicate of Macbook Pro won't boot after battery is depleted – BBlake Apr 18 '12 at 11:30
I guess the macbook clocks its cpu down on low power levels to save energy. no source for that, though. – Baarn Apr 18 '12 at 11:37
BBlake: I saw that question but it's not exactly the same symptom (mine doesn't take that long to start). And my question covers other stuff too. – Steve Bennett Apr 18 '12 at 11:58
up vote 1 down vote accepted

What you're experiencing is somewhat expected. As Walter said in the comments, once the battery is below a certain level, the system will try to conserve as much power as possible.

This includes stepping down the CPU, which explains the slow reaction for the first few minutes of usage (after the battery reaches a certain charge, everything's back to normal).

This is also why it's not recommended to run laptops without a battery, unless you want it to run more slowly — sounds weird, but I've seen that happen.

Your boot time increases since a file system check is run because of the unexpected shutdown. Any modern OS will do that by default.

There's not much to do about that other than trying to shut down your machine properly next time …

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Is it not possible to get the system to automatically hibernate below a certain battery level? Hell, my XP netbook does that - once it's down to a maybe 2%, it simply hibernates. – Steve Bennett Apr 20 '12 at 1:22
Yes, that should be the case, indicated by the loading bar during bootup. Given that yours won't hibernate.. How long does your battery last? What does pmset -g | grep hibernate tell you? – slhck Apr 20 '12 at 6:33
hibernatefile /var/vm/sleepimage hibernatemode 3 I get around 1-2 hours on battery - never really timed it. – Steve Bennett Apr 20 '12 at 6:49
That's not much, actually. Mode 3 writes RAM contents to disk (i.e. to your "hibernatefile", as indicated by pmset), so actually, in case of power loss, it shouldn't have restarted entirely. Maybe you could do a re-calibration — and while you do so, does the computer go to sleep or abruptly shut down? I could imagine that if your battery is broken, it won't allow the Mac to enter hibernation mode properly. – slhck Apr 20 '12 at 7:28

Data was not commited to disk when power ran out, thus disk was re-checked at boot and boot item cache aka hotlist was recreated. You need to check if your CMOS battery is in good condition too. I.e do you get your system clock reset when battery runs out?

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No issues with system time so far. – Steve Bennett Apr 18 '12 at 11:57
It is a natural way it works. If it repeats often you might want to use onyx or applejack to wipe specific cache and rebuild it. Such symptom generally means that one or more cells in battery are short-circuited and battery will start warming up quickly killing other cells if unplugged computer is ran at high load. Yes - you can order a new (aftermarket) battery, they are dirt cheap in this season – ZaB Apr 18 '12 at 14:07

If your charger is less that 80watt, Once the battery is completely flat the computer will not start for about 12 mins. Battery needs at least 1% charge before a Macbook Pro will boot when you use a charger lower than 80watt.

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