Force Windows 8 to use UTC when dealing with BIOS clock

Solution 1:

RealTimeIsUniversal is really buggy and not an officially recommended solution (maybe that's why they disabled it in Win8?) See IBM PC Real Time Clock should run in UT and a response from Raymond Chen here: Why does Windows keep your BIOS clock on local time?. As of date I don't think there's a proper solution for this.

Solution 2:

The default Windows Time service will always write local time to the hardware clock on shutdown, regardless of what the registry says about the real time being in UTC. Outside of this caveat, Windows will treat the hardware time clock correctly, if the registry is set correctly. Try this:

1. If the time is messed up from trying to get Windows to use UTC, boot into Windows, and set the time as it would be normally (correct timezone, no regedit, Windows Time service enabled, recently synced, etc)
2. Do the regedit you mentioned already
3. Sync the time w32tm /config /update
4. Disable Windows Time service sc config w32time start= disabled
5. Install a 3rd party NTP client
6. Verify that it works with a reboot