Last week, I have installed Ubuntu 16.04 on my Laptop alongside Windows 10 and chose OEM install during the installation just to try what it is up-to. Later, I learnt that OEM mode is a System Manufacturer Mode and choosing this would allow one to customise the OS before shipping to the end-users. This is definitely what I intended to do as a direct end-user. I, therefore, wanted to revert it to the normal user mode and this is how I did in just 1 step.
— Double click on “Prepare for shipping to the end user” icon in the Desktop. Upon rebooting, you will be asked for your preference (including name and username) and voila! you can login as a normal from then-on..