Recently LinuxAndUbuntu reader raised an issue that he was having with his dual boot. When he restarts from Ubuntu to Windows, the time in Windows changes. Here is why it happens and how you can fix it easily from Ubuntu.

​Pat Anablak asked a question that he is having trouble in keeping the time set in both OSes, Ubuntu, and Windows. This is what he was facing –

The time in Windows changes due to the ways both systems differently stores the time in the hardware clock. Ubuntu stores the time in UTC while Windows in Local time  so when user restarts Windows any number of time, the time does not change but when the user restarts from Windows into Ubuntu and then restarts back into Windows, the hardware clock has stored the time in UTC and now Windows changes it into Local time which causes the issue.

Time difference can easily be resolved by changing the time from UTC to Local in Ubuntu. To do this simply edit the “/etc/default/rcS” file and change “UTC=no” to “UTC=yes” (without quotes). Now Ubuntu will store time in hardware clock in Local time instead of UTC so there won’t be any conflictions between Ubuntu and Windows. To do this automatically, use the following command in terminal –

Although setting up time in UTC is beneficial because you don’t need to change the hardware clock when moving between timezones.

The above was the solution to the time difference from Ubuntu, now let’s see how to fix it from Windows -First of all download the below registry file and double click it to install.

After extracting registry, run command prompt as an administrator and enter the following command –

You are done! Now reboot the system for changes to take effects.