When i leave my macbook alone for a day (doesn't matter if it's asleep or off), and access it after, my clock is always slow about an hour.

I know this isn't an OSX issue, cause i use bootcamp too and the same thing happens there.

It also doesn't matter if i'm on battery or if i'm plugging in.

I'm certain it's not a time zone issue either... it can be slow 35 minutes, or slow 135 minutes, depending on how long i leave it alone. Its like the macbook is living in another time dimension.

Some piece of hardware on the macbook that is responsible for keeping the time is messed up... but i don't know what that piece of hardware is and if i can replace it.

Can someone tell me?


The clock time is keep by a battery or capacitor on some models. It is a small battery on the motherboard and used when the computer is off.

When the computer is on and online it will automatically update the clock time.

Normally that battery last 3-5 years.

Try setting the time manually, by getting the actual update for apple time server.

sudo ntpdate -u time.apple.com

then you will see something like

8 Jun 14:30:11 ntpdate[28267]: adjust time server offset 0.000336 sec

You generally don’t need to do this if you use the “Set date and time automatically” feature within the Date & Time settings.

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If that did not work, reset your SMC and PRAM (System management Controller)

I can not believe it is your battery but everything is possible :(. Assuming you do not have 2 left hands, you could do that your self.

  • P-RAM batteries used to be replaceable. Maybe an independent repair person. Definitely reset P-RAM first (aka NV-RAM) - your machine is new enough, that should do it. – Zo219 Jun 9 '13 at 1:21
  • i tried resetting pram and smc a few times, but the problem still exists. going to give it another go.. – Ralph N Jun 10 '13 at 3:16

after a long time, i figured out my problem.

So just to reiterate, my clock would not reset by some consistent number. But it would always reset around 3-5 hours, depending. I noticed it was doing it even during use. I would check the windows event log, and it showed that the hardware reset my time.

This happened to me twice after doing a CLEAN osx install, and then a CLEAN windows 8 install. After i install the bootcamp drivers, my clock was erratic in Windows 8.

I solved my problem when i went into OSX, and did a "get latest time from internet" (it was already set to automatic, but i explicitly made it do that). Afterwards, i reset back into Windows 8 and REINSTALLED the bootcamp drivers a second time. The second time... it did something that fixed the service that kept resetting my time. My time is always correct now.

So if you are having trouble, trying installing your bootcamp drivers TWICE. Must be a glitch in latest windows 8 drivers.

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