Ubuntu – Ubuntu 15.10 assumes BIOS clock is set to UTC time regardless of UTC=no in /etc/default/rcS


I have a dual boot system with Ubuntu 15.10 and Windows 10, so I tried to fix the time inconsistency between Ubuntu and Windows by applying the above mentioned widely known fix, but even after reboot Ubuntu keeps assuming that BIOS clock is set to UTC time, while I'd like it to be set to local time to be compatible with Windows.

From some comments to the same answer linked above, it seems that I'm not the only one that has this problem.

Any clue?

Why this question is not a duplicate

Question Clock time is off on dual boot is very generic, and among many possible solutions has the one of making Ubuntu use local time instead of UTC. But the widespread proposed way to achieve that does not work for me and others, so I think there is a need for another question asking why the widespread proposed solution of changing /etc/default/rcS does not work (at least in some cases), and my question addresses such need.

Best Answer

As @muru explained on Clock time is off on dual boot and according to the Arch Wiki:

You can set the hardware clock time standard through the command line. You can check what you have set to use by:

$ timedatectl | grep local

The hardware clock can be queried and set with the timedatectl command. To change the hardware clock time standard to localtime, use:

# timedatectl set-local-rtc 1

If you want to revert to the hardware clock being in UTC, do:

# timedatectl set-local-rtc 0

We can make Windows to use UTC but sometimes we have few Windows and only one Ubuntu for our multi boot setup. In this case preferable option is to force one Ubuntu to use 'Local' time rather than changing all Windows settings one by one.

Tested this method on Ubuntu 16.04 LTS Xenial and it's working without any issue.