Ubuntu corrupts Windows clock

[Erdal Ronahi]

I am using Ubuntu since Breezy through Dapper on several computers from different vendors in dual-boot mode with Windows XP. All releases and all computers have one problem:

After working in Ubuntu, if I reboot into Windows XP, the clock is two hours back. If I correct it, it will be corrupted after the next Ubuntu session again.

My timezone is Europe/Berlin, so I think the BIOS-clock may be reset to GMT. That would explain the 2 hours difference.

[istoyanov (istoyanov)]

Change the line in /etc/default/rcS that says "UTC=yes" to "UTC=no" and time shouldn't change anymore between OSes.

[istoyanov (istoyanov)]

The corresponding question -- whether to set system clock to UTC -- is also being asked during setup, so if you do future installs that should run on a dual boot (Linux/Windows) system just answer "NO" to that question.

[Erdal Ronahi (erdalronahi)]

I changed the line to "UTC=no".

However, I do not remember to have answered "yes" to the corresponding question. I do not even remember the question, so I stil suspect a bug.

How is Ubuntu able to change the system clock anyway so it influences other OSes? I think it shouldn't do that.

[Martey Dodoo (martey)]

"How is Ubuntu able to change the system clock anyway so it influences other OSes? I think it shouldn't do that."

Ubuntu and other flavors of Linux use a UTC clock by default (I assume so that changing timezones does not change your hardware clock); Windows does not.

[Erdal Ronahi (erdalronahi)]

To clarify: I use the same timezone in both OSes. I do not change it at all. Just booting into Ubuntu is enough to change the time in Windows.

[Vassilis Pandis (pandisv)]

Thanks for reporting this. It's not really a bug probably (unless you've set UTC to 'no' and it still happens) so I'm closing this report.