I installed Windows 7 (and XP before) on my Mackbook Pro and whenever I boot my Windows and after that boot my OS X my clock shows the wrong time and my login items that I set in the system disappear!

Someone told me that's because MBP don't have BIOS and that causes the problem to happen. Does anyone know how must I solve it?

P.S: I have also lost my second language added! Indeed I lost all my specimen settings.

  • How much does the clock change by, and what time zone are you in? It sounds like one OS is expecting the system clock to be in UTC and the other is expecting it in local time. – Stephen Jennings Jul 11 '10 at 18:04
  • I think it's Change randomly but about 3:30 from right clock. My time zone is Tehran, Iran (+03:30) – Am1rr3zA Jul 11 '10 at 18:09

It sounds like Mac OS X is expecting the computer's clock to be set to UTC, and Windows is expecting it to be in your local time zone, +3:30. When you boot Windows, it is synchronizing the clock with a time server on the Internet, noticing that your clock is 3:30 "slow", and adjusting it for you so your system clock now is storing local time (+3:30). Then when you boot back into Mac OS X, it thinks the system clock is still UTC, so it adds your offset again, for a total offset of +7:00.

Did you install the Boot Camp tools in Windows? If not, do that first and see if it fixes the time problem. I never had this problem, and sources online say that newer versions of Boot Camp tools take care of this for you.

If that doesn't work, in Windows, open the registry editor and navigate to the key:


and check the value of RealTimeIsUniversal. Change it to 1. That way Windows will store UTC time on the system clock, which is what Mac OS X is expecting.

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  • then It's effect on OS X? and what about My Login Item in Osx that disappear? – Am1rr3zA Jul 11 '10 at 18:21
  • and also yes I am install bootcamp tools in windows – Am1rr3zA Jul 11 '10 at 21:03
  • 2
    I don't know, but disappearing login items sound like something unrelated to time. You should create a second question for that issue. – Stephen Jennings Jul 11 '10 at 21:26

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