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Downsides of using UTC time by setting RealTimeIsUniversal
Hi,
I have a dual-boot machine where I use both Windows 11 and Linux.
To fix a minor annoyance with the hardware RTC clock always being set to the wrong time zone whenever I switch to the other OS, I know I can make Windows use UTC time by adding the RealTimeIsUniversal entry to the registry:
reg add "HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TimeZoneInformation" /v RealTimeIsUniversal /t REG_DWORD /d 1What are the downsides of making this change?
Are there any known issues, other than the usual caveats about using undocumented and unsupported registry keys?
Setting RealTimeIsUniversal to 1 tells Windows that the hardware clock is set to UTC, aligning it with Linux's expectations.
When this is enabled, Windows will interpret the hardware clock as UTC rather than local time.
2 Replies
I confirm that the appropriate system call gives the right result.
Probably the OS has to do some math, but it is not a problem with current hardware.
It IS actually possible nowdays tell Linux to use local time for RTS, but I disadvice it as Linux services are tipically more time-zone conscious than Windows application.
Setting RealTimeIsUniversal to 1 tells Windows that the hardware clock is set to UTC, aligning it with Linux's expectations.
When this is enabled, Windows will interpret the hardware clock as UTC rather than local time.
