Wrong time in Windows on Dual Boot system.

When you have a dual boot with Windows and Ubuntu you might experience some time travelling when rebooting to windows.
To solve this, simply boot into Ubuntu and edit the /etc/default/rcS file as sudo and change the UTC value from yes to no.
It should look like this

TMPTIME=0
SULOGIN=no
DELAYLOGIN=no
UTC=no #Set according to your system (BIOS) clock.
VERBOSE=no
EDITMOTD=yes
FSCKFIX=no

These values are being used by the scripts at /etc/rcS.d/ that get invoked during boot (even in single user mode)

To be clear, this is not an Ubuntu error. It is simply the Windows that never assumes the system-clock to be in UTC.

If you wish to adjust this in the Windows installation execute regedit and navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation

Change the RealTimeIsUniversal value to 1.

If you’re simply looking for a wach to change your hardwareclock on linux you can check my other article on Changing date and/or time on Linux.