I have a brand new Dell Precision Tower 5000 Series (5810) that just came with Ubuntu 14.04 pre-installed. Instead of upgrading to 16.04, I made a fresh installation (no dual boots).
I was not able to boot from USB, but luckily I had a DVD with 16.04. Installation using the DVD went with no problem.
During the installation, I was able to select Singapore as my location. However, once I opened Ubuntu for the first time, I noticed the following:
It is showing a totally incorrect time, around 7h ahead.
It claims it is Jakarta time (which is not) when I explicitly selected Singapore during the installation.
It shows weekday and month in Indonesian, even when everything is set to English.
It does not find anymore "Singapore" in the Time & Date settings, even when I was able to select it during installation.
Please check the images attached, at the time of writing this it's 9:20AM, not 4:20PM.