Macbook Air loses time when battery runs flat

Ever since I bought my MacBook Air nearly a year ago I’ve been plagued with a constant annoying problem, if I let the battery run completely flat, when I connect to a power source I get a warning saying my computers date is set earlier that March 24th 2001.


Your computer’s clock is set to a date before March 24th, 2001. This may cause some applications to behave erratically. Please use the Date & Time preference panel to set the clock manually. For more information, choose Mac Help from the Help menu.


Clicking on the clock in the top right corner of the screen does indeed show that the date and time is set to January 1st 2001. It normally shows midnight but it had been on charge for about 5 hours hence it’s showing 5:13am.

Almost all computers, both desktop and portables, have a small secondary battery on the motherboard (CMOS battery) which is used to keep the computer’s internal clock ticking when disconnected from the mains power supply or a notebook battery runs completely flat. It would appear that my MacBook Air‘s CMOS battery is defective and as such when the main battery is completely drained the onboard clock has no backup power source and loses the date and time.

Other than the annoying warning message it isn’t really too much of an problem for me though, I have had a few problems in the past joining my Windows domain at work as the domain server was reporting the MacBook Air had an illegal time stamp and a few outgoing emails have somehow been stamped with the wrong date/time although I thought they should have been stamped with my ISP’s SMTP server date/time?


Simply going into System Preferences


Date & Time


and then unticking and reticking the set date and time automatically check box



updates the internal clock with the correct details (as long as you are connected to a network).

I’m not sure how often OS X polls the NNTP servers for the time but I’m sure if I left it alone with the wrong date/time it would probably self-correct within half an hour or so of being connected to a network. I might run little snitch and see if I can see how often it’s pinging the server.

I have phoned Apple customer support and they have said this is obviously not normal behaviour, the onboard CMOS battery should be retaining the date/time for several weeks if the main battery is complete drained and the CMOS battery should recharge itself whenever the MacBook Air is connected to a power supply. It’s still under warranty for a few more weeks so I just need to take it in for repair but I’ve just not got around to it yet.

UPDATE 4th February 2009: I’ve just received my Macbook Air back from repair, along with a new screen/display unit it’s also had a completely brand new main battery. I called and spoke with the technician carrying out the repair and quizzed him about the faulty cmos battery and he informed me that most of the recent Macbook range including the Pro’s and the Air have phased out motherboard/cmos/clock batteries in favour of a capacitor based system in the MBA and small capacitor/onboard rechargeable battery in the others.. He said that even when your laptop battery doesn’t have enough power remaining to keep the disk spinning and screen on, there’s plenty left to power a simple onboard clock. As such the MacBook Air just has a small capacitor to power the clock if the main battery is left so long that it runs down completely. In my case, however, they ran tests on the battery and it was draining too quickly when the was only a few % left and was showing as faulty. For this reason they were authorised to replace the entire main battery and they have run some tests (not sure what tests) to confirm the problem is resolved. I’m very happy, I’ve looked at the stats on the new battery and it most certainly is new, showing at the time as only have 2 “cycles” (full charges) under it’s belt and 99% health.



UPDATE 12th March 2011: I am still plagued by this problem on the same Macbook Air a few years on. The only difference is now the warning says my computers date is set before January 1, 2008 whereas before it warned it was set before March 24, 2001. I’m guessing this is because I have now updated the OS to OS X 10.6.6 Snow Leopard?

Your computer's clock is set to a date before Jan 1, 2008.

43 Replies to “Macbook Air loses time when battery runs flat”

  1. I have had this problem lately. I brought it into the Apple Store, waiting 5+ hours because I didn’t have an appointment and needed to take care of it that day. Diagnostics showed no hardware issues. No battery issues. When this has happened to me, the main battery has been fully charged.

    As is often the case with the Apple Store…if they can’t figure it out…they just recommend wiping the entire thing and reinstalling the most recent operating system…which they did. That seemed to help get the computer to actually turn on (he claimed there was a software glitch with my old OS. But, even that day, later in the day, the computer is still turning on and off…especially if I close the screen, carry the laptop to another room, and then open the screen up.

    I’ve read about this issue on multiple boards and it’s been a problem with Apple laptops since back in 2008. And it doesn’t look like Apple has fixed, is going to fix it, or even really cares that much. That’s very disappointing given the premium I paid for a MAC. : (

    At this point, the general consensus opinions on what causes it vary…but:

    1) Bad battery, totally drained battery. Easy fix…don’t let your battery drop to 0%.
    2) Bad battery connection.
    3) Power cord (???…but replacing it has helped some folks)
    4) Motherboard connections

    At this point I have 4 choices:
    1) Keep it as is…deal with the annoyance…try not to move it around too much (nice laptop eh?)
    2) Try to back it up, wipe it, then send it in to Apple for repairs.
    3) Replace it with a newer Mac because apparently $3500 MacBook Pros only last 3 years.
    4) Replace it with a PC, learn to use the newest, most annoying Windows operating system yet, and get it for less than half that price with “as good” for less than half the cost…BUT you are going to have to constantly deal with viruses and malware and all that stuff…even with top of the line security software which seems to always be 1/2 step behind the hackers.

    Apple needs to take their zeal for R&D and inventing cool products…and focus a little more on quality and a LOT more on customer service. $3500 + 2yr Apple Care and once Apple Care expires I have to make an appointment and wait 30 minutes to 6 hours to talk to a live person at an Apple store where all they do is wipe the machine and install the newest operating system. Which works GREAT is your goal is to lose any information not backed up in Time Machine AND the added bonus of not being able to play any older video games because every 3-4 operating system updates…Apple changes something minor that makes older games unplayable. : (

    And don’t get me started on ITunes. I spent 3 hours last night trying to get music from my Ipod to my ITunes…and it looks like I now need to re-created every single playlist…after spending $19 on a software just to get the music transferred.

    Does anybody at Apple even care? Or are there just so many ultra-“cool” people that want Apple stickers for their car windows…that they’ll suffer through whatever nonsense Apple throws at them because it’s “cooler” than owning a PC??

    At this point, I’m going back to PC when I make my next purchase. I hate the new Windows more than anything…and I’ll be spending $100/year on virus protection that only ‘sort of’ works…but I guess I’m just too poor to continue to fund Apple’s dynasty at the expense of quality and any semblance of customer service.

    P.S. If your products actually worked well and were as intuitive to use as you claim (Apple)…you wouldn’t have 3-day wait periods for your Genius Bars and you wouldn’t need to charge people $49 to talk to customer service on the phone.

  2. Same problem but my battery died when I bought a new charger. My MacBook air, purchased in October 2011 is now a desk top. I could have it fixed for 100 pounds but what would be next? My laptop has been trouble after about 2012, I buy something new and something else goes. Out of warranty, can’t speak to anyone without being charged. Never again.

  3. macbook pro 2009 – doesn’t reset clock after battery drain. It never synced to any of the time servers from Day 1.

    I’m happy with the fact that I can do serious work without a BSOD or crash on my Macbook. But for the money I paid to Apple, this dumb battery problem is annoying as F*CK!

  4. I only just got this issue today. I have let my battery die countless times before and this issue has never happened to me. I have a macbook air I bought at the end of 2010.
    After my last restart I noticed that the clock would freeze at the time it last slept at and when it woke, it would continue, but at the wrong time.
    I had to go into time and date and click a few buttons before it would go back to the correct time.
    I then had the issue that the rest of you are describing except my internet became really bad so I restarted my computer and the time went crazy (1 jan 2001). I managed to fix it, but do you think I should take it in? There is not an actual mac store where I live (Only authorised retailers) and they were useless when they tried to fix my desktop.
    This only just happened to me but I am going to china soon (taking it with me) and do not want anything to happen to it whilst I am away.

    1. @sof – I am assuming you don’t have 3 years Apple Care and just the standard 1 year warranty? If it were me and my device was only 2 years old I would make a genius bar appointment and take it back to Apple even though it is out of warranty. Here in the UK we have some good laws to protect consumers who have bought items and specifically the “Sales of Goods Act” says that any item sold should be fit for purpose for a reasonable amount of time. For a TV this is around 4 years, for a laptop I’d say around 3 years. The onboard battery not holding charge (the problem you have) I would say is normal after 4 or 5 years but certainly not if you bought the computer in 2010.
      I would expect an Apple Genius appoint to result in a free of charge repair but there is no guarantee and since you do not have an official Apple store nearby my suggestion is of no help. You can try your reseller/repairer but I doubt they have the authority to repair an item out of warranty free of charge. Perhaps call Apple support and explain the issue, quite often they can authorise a free repair over the phone, you then just need to get it to an official Apple store somehow.
      Good luck and please update your post if you get it resolved.

      Scoopz (Admin)

  5. Same problem here. MacBook Pro 15″ 2009. Guess I going to use my last portion of apple care to fix this. Have had this issue for over two years now, have the issue every month or so.

  6. Same problem and MORE. In addition to the time and wifi password resets, I also lose whatever I had running before the battery ran out flat. It basically shuts down instead of sleeping/hibernating.

    Btw, the battery time remaining is incorrect (e.g. it will say 20 more minutes but then shuts down 5 minutes later, closing whatever unsaved work I had going on). Strangely, about 1 out of 15 times, under the exact circumstances as the other case, it will actually hibernate as it’s supposed to instead of shut down, thus saving my work. Can’t figure out why most of the time it doesn’t do that though.

    I have a late 2009 MBP15 running Snow Leopard.

    So there is no solution?

  7. I have been experiencing the same problems, time/date, wi-fi etc for the last two weeks on my 2009 macbook pro.

    It is the exact problem I had on my powerbook g4 after some years (I used it from 2003-2009).

    However, I am only having this problem after “downgrading” back to snow leopard from lion. Lion does some things with preserving memory before shutting down so upon restart everything is preserved – including the date/time etc.

    Other than that, I do not recommend Lion/Mountain Lion over Snow leopard. Unless of course you are running the latest hardware. But if that’s the case then you shouldn’t have any battery problems to begin with.

    Hope this helps.

  8. Hi, same problem here on MBP ; I understand clearly the advices of very very wise and smart people about 1) not letting battery run out and 2) reentering the wifi password to then let the clock resync itself with Apple time. Thanks for that, we *really* hadn’t thought about that ;o)
    Now, onto this piece of code from Mannarth : has anyone tried it, does it work, and if it works…well…what do I actually have to *do* with this code? Where do I put it in?

  9. Did anyone have time to try out the code that Manarth submitted, looks promising. Is there a way of fixing the proxy settings that get wiped as well? Not such a bad problem on a small scale but on a larger scale, horrendous.

  10. Well, I had a potential solution, but the system won’t let me post the script. Guess it’s some kind of antivirus/anti-XSS system, but it’s pretty poor because:
    1. It can’t tell the difference between sample bash code and an attack,
    and 2. It returns you to the blog page without any error message or notification, so first of all you lose the comment that you just wrote, and secondly you have no indication why it’s not posted properly.

    Ah well, it’s on if anyone cares.
    ————code start—————–

    me=”$(basename “$(test -L “$0” && readlink “$0” || echo “$0″)”)”
    now=`date +%s`
    filetime=`stat -f %m $me`

    if [ “$now” -lt “$filetime” ]; then
    echo “System time is too old. Updating system time.”
    date -f %s $filetime
    # Touch the file to update the mtime.
    touch $me
    ————code end—————–

    1. @Manarth – I’m not sure why the code got stripped out of your test comment, I’ll have to look into that. Thanks for taking the time to post you comment though and put the code on pastebin. I’ve copied the code from pastebin into your comment above for people to see.

      Scoopz (Admin)

  11. Workaround: I’ve found that if I plug in to ethernet (DHCP enabled) & reboot, time comes back to normal and WiFi is restored since the time server is able to sync over the wired connection.

    Bad news is I have 3000 machines to manage and not everyone has access to a patch cable. Actual solutions (not workarounds) would be a lifesaver at this point…yes Apple “Geniuses”, I’m talking to you.

  12. I have the same problem, but the last time the computer died, before setting back the date and time, I opened Evernote and it crashed. I set the time and date correctly thinking this might be the issue, but now, everytime I try to reopen it, it crashes. Haven’t been able to use it since then, uninstalled it, downloaded it again, but still keeps crashing…

    Anyone got a clue what this might be?


  13. Its not actually a problem. Happens on my Air as well. The workaround I do is as follows-

    as soon as the nonsense starts, change the date manually [any date 2011 is ok] and plug in. You must put 3% on the battery. Have a coffeebreak.

    restart the computer. the wifi should be ok now.

    go back into date/time & select auto.


  14. Why do you all keep complaining of the issue and no one here can clearly explain the fix. We know what the issue is – does any one have a resolution? If anyone here has had the problem resolved let it be known. Do not expound on what you think the issue is or this may be the issue. Simply put who has solved this issue and what did it take. Now, can I hear some responses.

    1. @Charles – Nobody has posted a fix because there is no simple fix. It’s not a software related issue it’s a hardware related issue i.e. your onboard CMOS/clock battery (not actually a battery but a capacitor I believe) has bitten the dust and is no longer able to hold charge for a reasonable amount of time.

      As pointed out in the article, I had my MacBook Air sent off for repair and they replaced the board that contains the clock battery in 2009 and that fixed the problem for a few years but now the problem is back. Nothing much I can do other than remember to go into system settings and tell it to check for the network date and time again. Annoying but there’s no way I’m paying for an out of warranty repair for this issue. You could always write a small shell script that runs whenever the computer resumes from sleep that automatically checks the NNTP servers, that may be the easiest solution assuming you are connected to the internet when you resume from sleep.

      Scoopz (Admin)

  15. Similar problem with my Macbook Pro. Battery died and even after resetting the date/time, all my e-mails show the date/time when the battery died. My warranty has expired so any ideas will be appreciated.

  16. Same problem here too with a Macbook Pro. Wifi password lost and clock reset :/ It’s out of warranty which is a bummer.

  17. Yup. Same problem here with my 2009 MacBook Pro. If the battery dies, the clock is reset and it forgets my wifi. It’s been like that since the day I bought it. Replacing the main battery isn’t going to fix this problem is it? Because if you let the new battery drain, won’t you still have this issue with the clock resetting?

    I’m out of AppleCare so a new motherboard is out of the question for me. What a piece of junk this computer is. I’m never buying Apple again. I feel like I got fleeced.

  18. I have the same issue with my Mid-2009 MacBook Pro (13 inch). The computer is not forgetting the password, but it can’t access the keychain because the date is fucked up. If you manually set the date to today, it should work again. If there’s no CMOS battery, it has to be the main battery or, worse, the mainboard. Crap.

  19. Same thing just happened to my MacBook Air 13″ 2010, battery drained and system turned off.

    I plugged it in, and it wouldn’t wake from sleep, so I hit the power button, it booted and displayed that the clock was reset and it forgot my Wifi password too.

    Very annoying. Macs forgetting Wifi passwords seem very common across all models.

  20. I believe the answer is a new motherboard, not a new battery 🙁
    Just sent one in for repair. As there isn’t a time battery, its a problem on the motherboard.

  21. Great article! I think it clearly states a common problem with the MBAir (and aparently other apple devices). I have have had the same problem but have yet to find a solution. I think we’re hooped until we buy the MBa2 and find out it has the same problem.

    “unticking and reticking the set date and time automatically check box” did not work for me. I have to do it by hand or wait until the mac decides it’s time to check the time.


  22. Same problem with MBAir 2010. Battery run’s flat (not connected to battery source over night eg); when I connect to power source, time clock is 2001; no wifi. Have found if reset time first; the wifi auto connects (so no need to insert passcode etc). iCal does alarm. I also have MBPro 2008 and have not had the issue at all. Agree, this is disappointing and more of a hassle than anything.

  23. Same problem with late 2010 Macbook Pro. If left to drain completely, it will not hibernate but completely die. Once turned on, it wipes out the clock and the wireless network password.

    Steve, is anyone from Apple reading these posts? Obviously there is a problem. Don’t make us vote with our feet.

  24. I have this same problem with a late-2010 Mac Book (white unibody). What I don’t understand is why can’t I set the computer to just sleep/hibernate once it gets to a critical battery level? Then I would just connect it to a power source and then start back up without losing data, time settings, wifi passwords, etc.


  25. Well I had this problem too, mid-2010 MBP.
    Battery run flat in sleep mode, March 2001 on wake, no wi-fi etc.
    But, even after connecting again to my wi-fi network, I couldn’t sync with time servers.
    It is not doing it, and I have to set it manually and then save it (it used to work though).
    I’m running Snow Leopard 10.6.7
    In /var/log/system.log I can’t see any network time activity.
    Could be some hardware problem?

  26. I have a simular problem with my iphone 4. When it runs out of battery it resets the time to Jan 1st 2001… Very annoying, do you think it is the same problem?

    1. @Linda – It could be a similar issue with the iPhone 4. My iPhone 4 battery dies quite often but I never lose the date and time on it. Make a Genius Bar appointment at your nearest Apple store and try and run the battery down before you visit to show them the problem. Failing that, try and get a video/photo evidence of the fault. They’ll swap it out for a new one straight away.
      Scoopz (Admin)

  27. I had the same experience as the rest of you on my MB Air Rev B late 2008 13″. Battery in good condition and nearly fully charged, but when started up warned that date set of 2000 etc. and network settings were lost. I had to re-allow dconfig and mdnsresponder network access.

    1. @Dale Cawthon – Thanks for the suggestion but resetting the SMC was one of the first things I tried as it has resolved issues on my Mac Pro before with Bluetooth issues, but in this situation it didn’t help.

      Scoopz (Admin)

  28. Just had it happen to my mid 2009 MBPro13″ for no apparent reason. Battery in good condition and fully charged, but when started up warned that date set pre March 2001 etc. and wifi password lost, all as others’ experiences above. Keychain wouldn’t let me in, either, but fortunately I had note of password so was able to get online and it sorted itself out when connection to apple europe time server regained, apparently.

  29. Same thing happens to my wife’s mid-2009 Macbook Pro (15″). When the main battery runs flat, the Macbook Pro loses the internal clock and gets reset back to year 2000. Together with the clock issue, it can no longer connected to the WPA2 network, whose password should be saved in Keychain. Therefore, NTP cannot obtain correct time. To fix this problem, I have to go to Keychain, delete the entry for my WPA2 Wi-Fi SSID, then enter the WPA2 password when connecting to the network, and then reboot the Macbook Pro for this password to stick. Otherwise, every time I try to disconnect from the WPA2 Wi-Fi network and then reconnect to it, I am prompted to re-enter the WPA2 password. It also appears that my wife’s iPhoto-to-Facebook integration got screwed up after the Macbook Pro’s battery ran flat. I guess I have to call Apple Care to get this fixed.

  30. Have the same prob with my 2009 MBPro. Lose wifi-key and time reverts to march 2001. Annoying, coz all my iCal alarms start ringing once reset!

  31. I have the same issue. My macbook is only a couple months old (basic 2009 Macbook) and if I ignore the low battery warning and let it run until it totally shuts down it will oftentimes (but not everytime) wipe out not only the clock, but my network password as well. (Not sure why the password gets lost due to the battery…strange).

    Hard to believe Apple dropped the use of a 10-year coin cell battery (that costs under $1 retail) and instead went with a capacitor or even a rechargeable battery. Obviously it was a very bad idea. Apple may be the king of innovation, but sometimes they should stick with things that are known to work quite reliably.

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