Jump to content

Apple Hw Clock

Recommended Posts

Quick explanation:

I have a hackintosh at hand (can't give info on that, sorry) and after booting into Mac OS X, then into Windows again, time is always misconfigured.

The explanation is simple: your computer's hardware clock. Windows stores time into it in whatever your local timezone is, while Mac OS X (and Linux and other serious operating systems) store it in GMT instead.

This program "fixes" your computer time when you boot up Windows, and then it puts time into GMT again when you shut it down/reboot it, thus solving the problem (you should disable Windows automatic time update from date/time settings).

Full explanation:

If you don't own an Intel Mac stop reading, this program is not useful to you (unless you have a multiboot Windows & Linux/UNIX/POSIX system and want to use GMT time in hardware clock).

Anyone owning an Intel Mac with both Mac OS X and Windows installed has suffered from this situation (unless your time zone happens to be GMT+0000 / UTC). I happen to have this problem too, let's see:

Windows stores time in local time zone.

Mac OS X stores time in global meridian time zone.

Of course BootCamp should solve the problem, but for those who still have problems, or those who are using alternate boot-loaders (grub, etc...) I wrote this alternative program.

It runs at Windows startup and sets hardware clock to local time.

Then, when you log out, sets hardware clock to gmt time again.

Of course if Windows crashes you'll have to fix the time by hand, but for everything else it works just fine.


- You'll have to disable Windows automatic time updates (time.microsoft.com, time.nist.gov or whatever).

- You'll have to uninstall any Windows NTP client.

- You'll have to disable Windows Time Service (run services.msc, find it, stop it and disable it).



Thanks File2Go!


I'll write an installer if anyone requests it.

Put AppleHWClock.exe into windows\system32 folder.

Run regedit.exe, go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run, and add an alphanumeric value, with name 'AppleHWClock' (or whatever) and value 'full:\path\to\windows\system32\AppleHWClock.exe' (usually C:\Windows\System32\AppleHWClock.exe)

Be sure your Windows has the right time zone, now boot into Mac OS X and let it update the time. If you're not connected to Internet, fix the time by hand.

Now boot into Windows and time should display ok, now reboot again into Mac OS X and time should be right there too. If not, then you did something wrong while installing.


If you run more than one session under Windows, using fast-switch feature, you'll see more than one AppleHWClock.exe process (one for each session). This is normal and correct, the last running instance of AppleHWClock will set hardware clock again to GMT, don't worry. ;)

Link to comment
  • 2 weeks later...

Please sign in to comment

You will be able to leave a comment after signing in

Sign In Now
  • Create New...