Recently I have came across many people asking how to install Ubuntu in a UEFI machine. Unified Extensible Firmware Interface (or UEFI for short) is a new type of firmware that was initially designed by Intel (known as EFI then) mainly for its Itanium based systems. It introduces new ways of booting an OS that is distinct from the commonly used "MBR boot code" method followed for BIOS systems. A detailed description of UEFI can be found at the ArchWiki or Wikipedia .  The installation remains similar to normal installation procedure but needs a little bit of tweaking. Having a PC with EFI firmware does not mean that you need to install Ubuntu in EFI mode. If you have a machine in which there is any operating system already installed in Legacy mode then you must install Ubuntu also in Legacy mode, unless you wish to format the system and start from scratch. If Ubuntu is the only operating system on your computer, then it does not matter, you can install Ubuntu in EF...