kagaku Posted September 30, 2009 Share Posted September 30, 2009 Odd problem that I never had before (had a Leopard install on here that worked fine). When I boot into OS X 10.6.1 the time will be correct - for instance consider that it's 10am. When I reboot and boot in to my Windows partition, Windows displays my time as +7 hours, so my 10am example in OS X above shows up as 5pm in Windows XP. Any idea what's going on? BIOS time reports the same as what Mac OS X shows, and when I boot back into OS X the time is correct - even if I manually fix it in Windows. My timezone is identical in both operating systems (CST) as well as DST settings. Link to comment Share on other sites More sharing options...
MacUser2525 Posted September 30, 2009 Share Posted September 30, 2009 Odd problem that I never had before (had a Leopard install on here that worked fine). When I boot into OS X 10.6.1 the time will be correct - for instance consider that it's 10am. When I reboot and boot in to my Windows partition, Windows displays my time as +7 hours, so my 10am example in OS X above shows up as 5pm in Windows XP. Any idea what's going on? BIOS time reports the same as what Mac OS X shows, and when I boot back into OS X the time is correct - even if I manually fix it in Windows. My timezone is identical in both operating systems (CST) as well as DST settings. Unix systems like OS X use universal time for their clocks windows on the other hand uses local time for the clock which is where you see the discrepancy you want to search on setting your windows install to use UTC via the registry setting that can be set for this. Link to comment Share on other sites More sharing options...
srs5694 Posted September 30, 2009 Share Posted September 30, 2009 See here: http://weblogs.asp.net/dfindley/archive/20...-Pro_2900_.aspx I seem to recall seeing reference to a fix in OS X, which causes it to read the hardware clock and interpret it as being set to local time. In my experience, it's better to set the hardware clock to UTC, though; this causes fewer problems surrounding Daylight Saving Time, since neither OS needs to adjust the hardware clock for this. Link to comment Share on other sites More sharing options...
Scottapotamas Posted October 1, 2009 Share Posted October 1, 2009 Here is one for OSX that Zeproth made... At boot and shutdown it toggles... Works in leo and hasn;t screwed my snow up yet so that a good sign Localtime_Toggle.pkg.zip Link to comment Share on other sites More sharing options...
srs5694 Posted October 1, 2009 Share Posted October 1, 2009 Anything that toggles the hardware clock at boot and shutdown will cause problems if the computer crashes. Thus, I'd avoid anything that works that way. It could be it's not a true hardware clock reset, though. That's how Linux, FreeBSD, and some other OSes that use UTC work; when they read a clock that's set to local time, they "translate" to UTC, then maintain the UTC internally while powered on. If so configure, they'll then adjust the hardware clock at shutdown time, but that's only to help with clock drift or to reset the hardware clock if the computer is powered on during a Daylight Saving Time (DST) clock shift. If the package to which you linked works more like that, then it's much less likely to cause problems. Such problems could still occur around DST, though, because two OSes could both try to change the clock. Link to comment Share on other sites More sharing options...
Scottapotamas Posted October 1, 2009 Share Posted October 1, 2009 it could work as you explained, as crashes or force rebooting into a different os haven't changed it... That was just what the guy who gave it to me said... Link to comment Share on other sites More sharing options...
imacken Posted October 1, 2009 Share Posted October 1, 2009 OK, FWIW, this is how I solved that problem. 1) make sure that your BIOS is set to your actual time, not the daylight saving time. So, for me in the UK, the BIOS is set to 1 hour earlier as we are on Summer Time (+1). 2) OS X should display the time correctly, but Windows doesn't. 3) To fix Windows time error create a new DWORD entry in the registry, i.e. HKLM\SYSTEM\CurrentControlSet\Control\TimeZoneInformation\RealTimeIsUniversal 4) set the value to 1. 5) reboot. You might have to do a Windows Internet Time sync, but it should work for you. Link to comment Share on other sites More sharing options...
srs5694 Posted October 1, 2009 Share Posted October 1, 2009 OK, FWIW, this is how I solved that problem.1) make sure that your BIOS is set to your actual time, not the daylight saving time. So, for me in the UK, the BIOS is set to 1 hour earlier as we are on Summer Time (+1). 2) OS X should display the time correctly, but Windows doesn't. 3) To fix Windows time error create a new DWORD entry in the registry, i.e. HKLM\SYSTEM\CurrentControlSet\Control\TimeZoneInformation\RealTimeIsUniversal 4) set the value to 1. 5) reboot. You might have to do a Windows Internet Time sync, but it should work for you. Step #1 is wrong, or at least confusingly phrased. This procedure is the same as the one in the URL to which I linked earlier, except that you should set your clock in the BIOS to Coordinated Universal Time (UTC), not to your local time without DST corrections, as you state. For you in the UK, the two happen to be the same, but for users even one time zone away, the two aren't the same. If you're not sure what the current UTC time is, try this site. It shows your current local time in a largeish font, assuming your time zone is set correctly; and it also shows the current UTC value in a smaller font near the bottom left of the page. Link to comment Share on other sites More sharing options...
zhang3feng Posted October 30, 2009 Share Posted October 30, 2009 Compiling from the above: 1) Upon successful installation / setting up of OSX (choosing your time zone), it will change BIOS time to UTC, leave it. 2) OSX should display the local time correctly upon reboot, but Windows doesn't. 3) To fix Windows time error, launch Regedit. 4) Go to: - HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation 5) Right click and create a new DWORD entry "RealTimeIsUniversal" 6) Set the value to 1. 6) Upon reboot, Windows should show the correct local time. Link to comment Share on other sites More sharing options...
imacken Posted October 30, 2009 Share Posted October 30, 2009 I've become quite confused by all this. I reinstalled Windows 7 the other day from the retail box - for no particularly good reason! - and with my BIOS time set to UTC, both OSX86 and W7 both display time correctly with no additional registry edit needed. Link to comment Share on other sites More sharing options...
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