Amrinder Singh Kohli
For disks larger than 2TB, you must convert the boot record from MBR(Master Boot Record) to GPT(GUID Partition Table).
MBR support 4 primary partitions and maximum hard disk upto 2TB.
However GPT support 128 primary partitions and support larger disks than 2TB.
This video shows how you can convert a MBR disk to GPT or a GPT disk to MBR.
Convert disk from MBR to GPT or from GPT to MBR
