For 3TB and 4TB hard drives you can create multiple partitions with full disk space without having to convert the MBR to GPT see how to partition a 4TB hard drive. MBR disks use the standard BIOS partition table. Select The Disk And Choose Convert Mbr Disk To Gpt Disk Create Partition Partition How To Apply Then select the disk and right-click it to chooseConvert to GPT diskfeature. How to convert system disk from mbr to gpt . To convert a GPT disk to MBR using the Disk Management utility follow these instructions. Windows Vista Windows 7 and Windows 8 or 81. However if its a system disk make sure your operating system and motherboard are supported to boot from UEFI mode before converting the disk to GPT since the system GPT disk can only be booted from UEFI mode. In previous versions of Windows you were forced to reinstall the entire operating system if you wanted to convert Legacy BIOS or Master Boot Record MBR to UEFI or GUID Partition Table GPT. If the data is overwrit...