The format used to define the hard disk partitions in computers with UEFI startup firmware. The GUID Partition Table (GPT) replaces the previous master boot record (MBR).

Note that this command works only on Intel Macs with hard disks formatted using the GPT (GUID Partition Table) format with a journaled Hierarchical File System Plus (HFS+) file system.

This post explains what is MBR (Master Boot Record), GPT (GUID Partition Table) and which technology is better for your SSD.

Create two partitions on your drive, both using a GUID partition table. Format at the OS X partition as Mac OS X Journaled and the Windows partition as MS DOS FAT.

MBR is the abbreviation of master bootable record, whereas GPT is an abbreviation of GUID partition table. In order to boot Windows from GPT, the motherboard of the device should support UEFI ...

This may be related to either a partition scheme problem or a driver limitation on certain configuration. First check that it's partitioned as GUID Partition Table (GPT), not Master Boot Record (MBR).

To do so, select the drive in Disk Utility, click the Partition tab, select 1 Partition from the Volume Scheme pop-up menu, click the Options button, choose GUID Partition Table or Apple Partition ...

To partition and format a disk in OS X, ... The second option is to use the "gpt" command (for managing GUID partition tables) to destroy the current GUID partition table on the device.