Windows and boot disks larger than 2TB #

Windows' Support for Disks with Capacity Greater than 2TB:

In order for a system to fully support capacities greater than 2TB, the device must be initialized using the GPT partitioning scheme to support addressing the full range of capacity. If the user is intending to boot from one of these large disks, there is an additional requirement that the system's base firmware interface must be using UEFI and not BIOS.

Windows and GPT FAQ:

Q. Can Windows 7, Windows Vista, and Windows Server 2008 read, write, and boot from GPT disks?
A. Yes, all versions can use GPT partitioned disks for data. Booting is only supported for 64-bit editions on UEFI-based systems.

So to create bootable partitions larger than 2TB for Windows-based OSes:

UEFI instead of BIOS
GUID Partition Table (GPT) instead of Master Boot Record (MBR)
64-bit version of Windows Vista, 7, or 2008

It may be possible to non-destructively convert or migrate a Windows boot disk from MBR to GPT:

GPT fdisk can "convert an MBR disk to GPT format without data loss ... although doing so will require you to re-install your boot loader (if it's a boot disk). Do not attempt to convert a Windows boot disk from MBR to GPT form unless you're an expert!"
Gptgen "is a tool to non-destructively convert hard disks partitioned in the common, 'MSDOS-style' MBR scheme (including extended partitions) to use a GUID partition table (GPT)." Walkthru
Macrium Reflect can apparently clone an MBR disk to a GPT disk.

Rod Smith, the author of GPT fdisk, offers detailed GPT documentation, including:

/windows | Apr 22, 2012

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