System Time is Wrong in Windows 7 after dual booting Ubuntu

  • naithemilkman

    After installing Ubuntu, the time in my Windows 7 is wrong on start up. Even after updating the time in the Internet Time Settings manually, it still reverts back to the incorrect time after a while.

    This fix seems to do the job for most people but I does not work for me. The time in Ubuntu is correct.

    I've searched high and low for a solution?

  • Answers
  • Ben Kraft

    The issue is that Linux generally prefers to keep the BIOS clock in UTC, whereas Windows prefers to keep it in local time. It may be easier to get Ubuntu to keep it in local time than to get Windows to keep it in UTC, even though UTC is probably Better. This page (towards the bottom) gives instructions for both; it looks like the Windows-side fix is probably the same as what you've already tried, but hopefully the Ubuntu-side one will work.

  • bubu

    maybe you can check if your ubuntu timezone is connectly set. also if you use a local time server, check if the timeserver is correct. if i remember correctly some flavor of linux do 'restore time on startup'...

  • Related Question

    Windows computer keeps updating to UTC time
  • Daniel H

    I have a new Dell computer running Windows 7 x64 (and no other OS). I live in Mountain Time, as my computer is aware (it says Mountain Time in the Date and Time window, from right-clicking on the taskbar clock and selecting Adjust date/time). However, often, it updates to say a time that's six hours later than it should be. I assume that it's updating to UTC and once Daylight Savings Time is over, it will start updating to seven hours later (assuming that I can't solve it by then and nobody answers this). When I tell it to update the time from the Internet (, it updates to Mountain Time again, though, at some later point, it will again switch to UTC.

    Obviously, this behavior is undesirable, as I would like Windows to know what time it really is. Is there any way to fix this?

    Update 20 Oct 2010 - I do not believe I have any programs installed that could adjust the clock. I do, however, occasionally boot into Linux Mint Live CD (I've been meaning to install it on my hard drive, but haven't yet), though I doubt this is the problem because the times I've noticed were nowhere near the times that I used the Live CD. After applying the fix below, I haven't really noticed the problem again, though I did manually mess with my clock a bit, which may have masked or shown the symptoms. If I everything is still good in a week, and again once DST is over, I'll answer the question with the fix mentioned below.

    I'm trying the solution here, but this isn't easily reproducible (I need to wait for some amount of time, and I'm not sure what that amount is), so I'm posting this question in hopes that somebody can verify if that answer will work or can provide another answer.

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  • Canadian Luke

    (@MBraedley's feeling above seems correct to me.)

    Most (if not all?) Linux systems use UTC by default for system time, and have NTP enabled. If Windows is not using NTP to keep the time updated, then I would expect the time to show incorrectly when booting to Windows after using Linux.

    If that is the case, you would have two choices:

    1. Disable UTC in Linux (Set UTC=no in your /etc/default/rcS in a Debian derived system), or
    2. Use UTC in Windows 7 - just found this in another * post but already lost the link.

    (I think Windows default of using local time as systems time is kind of dumb; personally I like the idea of using UTC as system time much suitable choice.)

    I am not familiar with Windows 7 and if it is using NTP by default. Enabling NTP in Windows (if not already enabled) could also be a workable solution?