Does Windows 7 support UTC as BIOS time?
Since I live in Germany, my timezone is GMT+1 (or GMT+2 in the summertime period). Previous Windows versions were not able to have the hardware clock set to UTC, and the Windows time to the local time. That was / is a big mess, since almoust every other OS is using UTC preferedly.
Is this fixed in Windows 7 and is it now possible to use UTC in the BIOS and local time in Windows?
Have a look at this page:
Save the following lines as
utc.reg,and then run it to import this registry tweak. It allows you to set the hardware clock in your PC’s BIOS to UTC time. This is handy for boot dual-booting Mac, or Linux, when those operating systems are set to read the BIOS clock as UTC time, instead of Windows’ preferred Local Time (e.g., PST, PDT, MST, MDT, CST, CDT, EST, EDT, or the standard “GMT-” and “GMT+”)
Here is the code to save as utc.reg:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation]
"RealTimeIsUniversal"=dword:00000001
The equivalent answer can also be found here.
Windows 7 support for UTC time in the RTC is at this time incomplete (July 2013), and not recommended by sysadmins who have tried to make use of it.
The site recommended by grawity above includes a useful summary of the state of this problem.
Currently, if you enable "RealTimeIsUniversal", occasionally the system time gets reset to a wrong time (UTC minus local offset). This causes the DHCP client to fail to refresh the dhcp lease and the system becomes disconnected until you manually refresh the lease, or restart the DHCP client.
Finding a workaround for this particular bug may be an acceptable tradeoff, but there might be other subtle bugs that come and go as Windows gets updated, due to the fact that the "RealTimeIsUniversal=1" configuration is not regression tested at Microsoft presently.
I want to add this link http://www.nathanhunstad.com/blog/2012/01/windows-7-utc-time-issue/ in which explains that sometimes Windows doesn't update the BIOS clock, but does make the UTC->Local time conversion.
The key is to make the change in the BIOS manually and Windows won't change it. It also speaks that Internet Time won't work correctly.
Hope it's interesting for you and find it usefull!