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There are many things that most people take for granted. One of them is that clocks always show the current time. When you tend to rely on your computer’s time and your computer clock loses time, this can be fatal.

There are several situations where the Windows clock starts showing the wrong time. If you’re obsessed with having the exact time on your computer no matter what, you may want to set up synchronization with a remote server. Before you do that however, please note that an inaccurate Windows clock should not be taken lightly.

If the computer clock loses time although you keep fixing it, there may be a serious cause. This article shows you what the underlying causes may be and how you can fix them.

1. CMOS Battery

This is the most likely scenario, especially if your computer is not brand new.

The CMOS battery sits on your computer’s motherboard and provides power to the Complementary Metal Oxide Semiconductor (CMOS) chip. The CMOS chip stores information about the system configuration, including the date and time. The CMOS battery makes sure the chip can store this data even while the computer is turned off and not hooked up to power. If the battery goes bad, the chip starts losing information and one of the symptoms is that your computer no longer maintains its time and date.

computer clock loses time


Replacing the CMOS battery is pretty easy. You just have to turn off your computer, ground yourself, open the case, find out which type of battery (step 3 in the linked guide) sits on your motherboard, go buy it, start over, and exchange the battery. Follow the links to the keywords for articles on the respective steps.

2. Time Zone

This is an easy to fix cause for when your computer clock loses time.

Your computer may simply be set to the wrong time zone and every time you fix the time, it resets itself to that time zone when you reboot. If the minutes are correct and only the hour is bad, that’s probably the issue you’re dealing with.

In Windows 7 you can easily fix the time zone. Right-click the system clock in your taskbar and select > Adjust date/time. Under the headline > Time Zone check whether the information is correct. If not, click the > Change time zone… button and set your time zone. Don’t forget to confirm your changes and you’re all set.

computer clock not keeping time

3. Malware

This is the least pleasant and most difficult to manage scenario.

Your computer may have been hijacked by a virus that messes with your computer time. To fix it, you need to gather a few tools. First, make sure your anti-virus program is up to date with the latest virus definitions. Then get a good malware scanner, for example Malwarebytes Stop & Delete Spyware With Malwarebytes for Windows Stop & Delete Spyware With Malwarebytes for Windows Read More or Spybot Search & Destroy. For more tools and links to the respective download pages, check out our The Best Of: Windows Software page.

Once you have all these tools downloaded, updated and installed, start in Safe Mode How To Start In Windows Safe Mode & Its Uses How To Start In Windows Safe Mode & Its Uses Read More and run them. It’s important to start in safe mode because the malware won’t launch and be active when you choose this boot mode. This means that it is less likely to escape detection and removal.

computer clock loses time


It’s important to pay attention to the most basic features of your computer. Simple things going wrong can be a sign of serious trouble ahead. For example if your CMOS battery dies, your computer will act like it has Alzheimers and you have to introduce it to its hardware components (via the BIOS) every time it boots. That’s just as annoying as a virus that plays tricks on you or a bad time zone setting that messes up everything from the clock to your email client’s time stamps. So be wise and act immediately.

Be sure to also check out Jeffry’s article How to Make All Your PC Times Match With an Atomic Clock Sync How to Make All Your PC Times Match With an Atomic Clock Sync How do you ensure that your computer clock is accurate? We show you how your system clock works, how to customize its settings, and what to do if it starts displaying the incorrect time. Read More on synchronizing your PC clock with an atomic clock.

Do you sync the time on your computer and what made you set that up?

Image credits: Gina Sanders, Peter J. Kovacs

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  1. Winnie
    April 3, 2017 at 2:40 am


    I bought my PC in 2011. 2 months ago, the date on my pc starts to show inaccurate time and the CMOS battery was replaced. My problem starts after replacing the CMOS battery. During use (sometimes after 1 hour usage and sometimes 20 minutes usage), the monitor will suddenly black out but the CPU continues running. This happens many times. I have taken the monitor and CPU to the shop for checking a few times. The shop said everything is fine with the monitor and CPU. I am at my wits end. Please help

    • Tina Sieber
      April 6, 2017 at 4:20 pm

      Hi Winnie, Black Screen issues can have a host of causes and this is not necessarily related to the CMOS batter replacement.

      Look into this article on fixing Black Screen issues and hopefully one of those fixes will work for you.

      Do let us know what it was when you find out. Thank you in advance!

  2. habib shukur
    February 18, 2017 at 11:56 pm

    thank you!. I got good information

    • Tina Sieber
      February 20, 2017 at 5:29 pm

      Glad to hear, Habib!

  3. Andrew
    November 16, 2016 at 3:58 am

    whis happens to Business laptops aswell

    • Tina Sieber
      November 16, 2016 at 10:04 am

      And why wouldn't it?

  4. chandra sekhar
    October 30, 2016 at 6:52 am

    Thank you, timezone correction helped me to correct time

  5. Vikram
    August 30, 2016 at 2:36 pm

    Error 0271: Check date and time settings
    0251: System CMOS checksum bad - Default configuration used

    This is the error appearing whenever i start my laptop.

    Can any one tell me what to do?

    • Tina Sieber
      August 30, 2016 at 6:58 pm

      Have you tried to take out the CMOS battery or to replace it?

  6. sonu
    August 9, 2016 at 11:26 am

    my pc clock stops working when i shut it down ..i.e it starts back from where it halted.though i changed my bios battery 4 times , i still aint find anything useful

    • Tina Sieber
      August 9, 2016 at 11:51 am

      That is very weird behavior. What kind of PC is it?

  7. Masoud
    July 21, 2016 at 12:50 pm

    Finally after several month and changing about 4 CMOS battery, I fixed my computer clock problem, just with updating the Bios.

    • Tina Sieber
      July 21, 2016 at 5:10 pm

      Thanks for sharing your solution, Masoud!

      • AVi cool
        August 22, 2016 at 5:16 pm give me big knowledge..thnx
        mam how to connect with you.
        please can you tell me ur fb/tw account,any social acc//

  8. Shankar Karmakar
    June 25, 2016 at 7:09 am

    It's Good & Very Useful Information..


  9. toad456
    June 16, 2016 at 7:36 am

    My problem is slightly different when my pc is on automatic it sets to about 30 mins behind the current time at first i solved this by turning the "set time automatically" off. However recently it has been losing time again. I removed a trojan yesterday but the problem still hasn't been resolved.I had my bios battery checked about 2 months ago and it was in perfect working order.

    Have you got any sugguestions?

    • Tina Sieber
      June 17, 2016 at 2:13 am

      You say you removed a Trojan. How do you know your system is clean now?

      Which version of Windows are you running? Did you set the right time zone?

  10. Jeep Lady
    May 20, 2016 at 9:11 am

    Good and useful for me. Thanks........

    • Tina Sieber
      May 21, 2016 at 10:42 am

      Hope you're on time again. :)

  11. Avneet Singh
    May 17, 2016 at 3:22 pm

    i am using window 7 ultimate 32 bit and i am still facing this problem.. when i click at timezone button i am not able to see option automatically adjust clock for day light saving. so that time of the window will changed again and again.. kindly help me

    • Tina Sieber
      May 21, 2016 at 10:42 am

      Did you try everything above? Is this an old computer? Have you tried replacing the CMOS battery?

  12. janaka.sanda
    March 24, 2016 at 4:01 pm

    thank you....

  13. amarjit singh
    November 12, 2015 at 8:53 am

    good information..

  14. Lindsay Long Spfd MO
    May 24, 2015 at 11:03 pm

    Super Duper Tina! Thanks so much!

    This computer i recently bought was on Pacific time. i Am in Central time. One click , fixed done!!

    • Tina Sieber
      May 25, 2015 at 12:42 pm

      Glad it was such an easy fix, Lindsay!

  15. Ibrahim
    May 20, 2015 at 5:59 am

    Thank you for the feedback it helps to know the reason why my computer does not automatically change date time

    ibrahim mwarimbo

  16. Melia
    May 19, 2015 at 10:48 pm

    Dual Problem for me: I shut down, then hours later computer has rebooted itself to system window and tells me to "F1", where it enters the bios with wrong time. I have tried resetting to "windows-time" as well as other time servers sychronized thru internet, I have tried manually resetting; Nothing works. Bad CMOS? Took it to store within year of purchase, they said nothing wrong. Should I disable APM (Advanced Power Management)? Is it a monitor power saving option that is interfering? I have run Malware detection, virus detection, all clean.....Very frustrating. Thanks.

  17. dw817
    May 8, 2015 at 4:16 pm

    Thanks ! That seems to have fixed it. Had the wrong country code.

  18. Sladjan
    April 10, 2015 at 7:39 pm

    I have some strange problem with time sync on Windows 7. Almost every time when some of my colleagues starts to move/save some data to HDD (not system drive) from one of our servers, system starts to lose time sync (up to 45 seconds forward at that moment when they press on save confirmation button). Problem remains even after fresh system install.

    What do you think, can a damaged HDD cause losing time sync?

    System drive is 500GB WD and data drive/partition is 2x 1TBWD in RAID.

    • areeb
      April 29, 2015 at 10:03 pm

      my computer sometimes shows date 2815 and shows its out of calendar reach then all https sites are blocked.......... it had happened like 3 to 4 times and i restore my computer then the problem is to fix it permanently

  19. Mort
    March 30, 2015 at 8:47 pm

    The clock has been reset again!
    Should I try the other three or four servers as well? Is this a bug? Is it that there is still some setting kept which I should not keep? To my knowledge, I have unticked everything...

    • Tina
      April 1, 2015 at 8:39 am

      Don't think that will make a difference. The problem must lie elsewhere. Again, I recommend to ask someone over at MakeUseOf Answers.

  20. Mort
    March 30, 2015 at 11:01 am

    I have done that just now; thank you!
    The server immediately reset the clock to show a different time. I manually set it to show the time I need.
    All I have to do now is wait and see. If there is no resetting in the next twelve hours, it might be OK.

  21. Mort
    March 28, 2015 at 8:15 pm

    Sorry, I meant "Windows 8 or earlier".
    I am on Windows 8.1.

    • Tina
      March 30, 2015 at 9:45 am

      Mort, did you try Rich's tip from above and change the time server?

      Click > clock in system tray > Change date and time settings... > Internet Time tab > Change settings... > switch server to or other.

  22. Mort
    March 28, 2015 at 7:10 am

    Hey there!
    It is not Windows 10.
    I do not want to change the region. I want to keep things the way they are and still have the clock show the time I want it to show.
    I do not want the system to take decisions for me. I should be the one in control, not the machine.

    • Tina
      March 28, 2015 at 6:11 pm

      I see where you're coming from, Mort.

      I thought you were on Windows 10 because you said it didn't happen on the previous Windows (8 or older). Are you on Windows 8/.1 then?

      You should post your question to MakeUseOf Answers for support. I'm not sure why this is happening.

  23. Mort
    March 26, 2015 at 7:41 am

    I keep a certain time zone on my computer, which has nothing to do with where I live. Windows changes the clock two or three times a days regardless of the fact that I require that it should not do so. This did not happen on the previous Windows (8 or older) versions of the OS. Why is this happening now and what can be done to make it stop? (It is really annoying.)
    Thank you very much!

    • Tina
      March 27, 2015 at 8:31 pm

      Is this Windows 8.1 or 10? Have you also tried changing your region to the respective (desired) time zone?

  24. seamus Glas
    March 12, 2015 at 10:30 pm

    where is this cmos battery on my e-system laptop so I can exchange it.

  25. Omer Ahmed
    March 8, 2015 at 2:34 am

    Thanks Tina | For sharing such a good Info.

  26. Rich F
    January 18, 2015 at 2:46 am

    Well people, your CMOS battery (on the motherboard) is only in use when you UNPLUG the computer from a continuous power source. In other words, your computer does NOT even require a CMOS battery unless you unplug it from the wall!

    So why does my clock run slow, reset, or my date and time change when I reboot? Who knows! If you do NOT unplug your computer and your clock resets to 1999 or some other date, your clock crystal is failing or has failed, or there is a problem with the PLC, or there might even be a problem with the Southbridge of the processor. There are several non-user serviceable reasons. The CMOS battery is the only thing you can service and is probably not your problem!

    Remember, CMOS batteries only hold your BIOS settings when your computer is unplugged.

  27. Rich Green
    January 1, 2015 at 6:48 am

    Windows provides an option to sync time to an external time server. I had a similar problem with my PC using Windows 7. I also dual boot with Linux. Linux time has always been accurate, so my issue was not cmos battery related.

    My solution in W7 was to simply change the Internet time server. Click on clock, then "change date and time setting", ... click on tab "Internet settings." Make sure your clock is using Internet settings. Click on "change settings".... and select a different time server . Remarkably, some time servers W7 proides are defunct or don't provide accurate time. I use:

    • Tina
      January 1, 2015 at 11:48 am

      Thank you for the advice, Rich!

    • steve
      February 13, 2015 at 2:21 pm

      Thanks, Rich. My Win7 was off one hour, even though it was set to the correct time zone. I switched it to a.nist.gove. It seems to have worked ---- I'll see after thye next boot.

    • eliza
      March 30, 2015 at 9:36 am

      Thank you Rich, your solution solved my prolem.i changed the time server and its now ok.

  28. zizi
    December 30, 2014 at 6:38 pm

    thank you so much, I solved my problem.

  29. Kay
    February 22, 2011 at 5:46 pm

    My computer clock often shows the wrong time & date - even back when I had just bought it. So I just reset the time and date. This happens at times when I turn it on and the BIOS update screen is there and then windows loads normally with, of course, the wrong date and time.
    I think I send it back to HP to fix this "weak" battery.

  30. Denny Wilson1979
    January 18, 2011 at 1:11 pm

    I am facing the same issue, Tina tons of thanx for this post :)

    • Tina
      January 18, 2011 at 5:52 pm

      Glad to hear the article was helpful. Thanks for the feedback, Danny!

  31. Doc
    January 14, 2011 at 8:56 pm

    Another problem (which will adjust your clock by 1 hour either way) might be your Daylight Savings Time settings may be out of date (there's been at least 1 change to the DST rules since 2007). Windows Update will take care of this, as will some third-party updaters for Windows 98 and up.

  32. Tina
    January 14, 2011 at 9:18 pm

    I would say 3 to 5 years is the lifetime you can expect. After the third year you should be aware of the possibility that the battery might start losing it.

    However, I have seen computers that were over 7 years old and they were ok. The time wasn't accurate, but it wasn't dramatically off either. Most importantly, there were no boot issues, i.e. the battery was still providing enough power to store the BIOS settings.

  33. James T. Kirk
    January 14, 2011 at 2:38 pm

    The time server (NTP server) that Windows uses to sync may be down or not reachable. A PC clock is very inaccurate and will go out of sync even without battery problems. Make sure, the NTP server is up and reachable.

    • Tina
      January 14, 2011 at 8:14 pm

      Good point!

  34. Eric Darchis
    January 14, 2011 at 9:32 am

    There is a (1B) too: my motherboard has a few switches at the back, near the USB connectors. One of these switches is a CMOS reset. I accidentally switched it and wondered why I would lose the settings when turning the computer off completely.

    So if your battery is recent, you might look at the motherboard manual and see whether the CMOS clear switches are properly turned off.

    • Tina
      January 14, 2011 at 8:15 pm

      Thanks for bringing this up, Eric! I was not aware of a CMOS reset switch.

  35. Eric Darchis
    January 14, 2011 at 10:32 am

    There is a (1B) too: my motherboard has a few switches at the back, near the USB connectors. One of these switches is a CMOS reset. I accidentally switched it and wondered why I would lose the settings when turning the computer off completely.

    So if your battery is recent, you might look at the motherboard manual and see whether the CMOS clear switches are properly turned off.

  36. Tonergreen
    January 14, 2011 at 8:24 am

    That's probably why my PC clock do not match with our office time-in clock. Hmm... I often complain about the time-in clock being adjusted without notifying us. I will have a check later.

    But normally, how long will it take for the CMOS battery to start showing signs of malfunction since its the PC is assembled and installed?

    • Aibek
      January 14, 2011 at 12:29 pm

      Based on my personal experience chance are you won't have to change your CMOS batter at all unless you have been using the same desktop for over 5 years.

      • Tina
        January 14, 2011 at 8:18 pm

        I would say 3 to 5 years is the lifetime you can expect. After the third year you should be aware of the possibility that the battery might start losing it.

        However, I have seen computers that were over 7 years old and they were ok. The time wasn't accurate, but it wasn't dramatically off either. Most importantly, there were no boot issues, i.e. the battery was still providing enough power to store the BIOS settings.

    • Fev
      January 13, 2015 at 6:05 pm

      My computer started showing signs of CMOS malfunction since 4 years ago one of them is keep resetting the time, but other than that, i feel my computer is just fine !