Explained Why Bootcamp’s Windows Clock Always Off and How to Fix it


With Bootcamp, it’s easy to install Windows on a Mac, but there are problems. Even with the latest Bootcamp 5 Apple released few weeks ago, they still remain unfixed. For instance, you will notice that when you reboot your Mac switching between Mac and Windows your Windows’s clock is always off (unless you live at GTM+0 area). In fact, it’s always off by your local GMT offsets. If you live on the west cost of North America, you will notice the hour is off by 7 to 8 hours, depending on where you are. This is because in Mac and most Linux they use GMT time where as in Windows they use something else, so every time when your Mac reboots into Windows it tries to convert the value from GMT.

How to Fix Windows To Display Correct Clock

Go launch Windows regedit.exe


Navigate to



Right click add a new DWORD(32-bit) value key


Name the key to RealTimeIsUniversal, give it a value 1


When you done as the above, on your next restart, your Windows will getting the correct time instead off by your GMT offsets.



  1. This is maddening. This registry setting was already there for me and set correctly, and yet my clock is still wrong. It’s not wrong by my GMT offset either (-5), it’s wrong by +4. For instance, right now it shows 10:46AM, not 2:46PM. Grrrrr

    I’m not sure why I even updated. The only real problem I had before was not being able to hot-swap my lightning bolt gigabit ethernet adapter, and that is still broken. The only other issue was needing to set my account as a non-admin to open the BC control panel, but that’s OK because once I changed those settings I never needed to open it again. I rarely boot to OSX (much less from Windows) so having that work was never something I cared about.

    Frustrating they can’t get this stuff together..

      • Worked for me. After upgrading to Boot Camp 5, I had to set that value to 0 to make things work. It was already there and set to 1.

  2. I am running Windows 8 on a Macbook pro. No OSX just a clean Windows 8 install. After upgrading Bootcamp the other day, my clock has kept changing it self. Setting it self ahead 2 hours. That’s annoying but it also messes with programs that depends on the clock. After reading this article I found that I already had RealTimeIsUniversal set to 1 in my reg db. I removed it, restarted and so far my clock is working as it should.

  3. I was having the problem when I booted back to MacOS the time would be set to GMT. I followed these instructions and this has corrected my problem. Thanks.


Please enter your comment!
Please enter your name here