Hard drives greater than 2 TB do not work on existing operating systems

2TB hard drive External USB, eSATA, Firewire, and internal hard drives over 2 TB’s cannot be formatted on Windows 32-bit operating systems using the Master Boot Record (MBR) partitioning scheme. As a result, when you connect drives over 2 TB’s, depending on which interface you are using to connect them to the computer, they may not be recognized at all, they may be only partially recognized, or they may be recognized but you can’t access them. Other issues such as the system locking up or the computer not being able to boot may also occur.

This not an external or internal hard drive issue. It is a 2 TB volume limitation caused by the Master Boot Record (MBR) partitioning scheme that has long been used by Windows 32-bit operating systems such us Windows 2000 and XP.

In order to use a drive larger than 2 TB’s, you will need an operating system that can partition and format that drive. Windows Vista, Windows XP (64-bit), Mac 10.4, and Mac 10.5 all have this capability through the GUID Partitioning Table (GPT). The GUID partitioning scheme has the ability to partition both internal and external drives far beyond 2 TB’s in size.

Below are some things to keep in mind when considering the use of drives larger than 2 TB’s:

  1. Windows 2000/XP (32-bit) has no issues with Network storage drives larger than 2 TB’s since they are accessed indirectly through the network.
  2. Windows XP (64-bit) only recognizes external hard drives larger than 2 TB’s that are connected by USB.
  3. You need to know in which partition scheme, MBR or GPT, your Windows Vista operating system is installed. If it’s MBR, you will still have the same issues as in Windows 2000 and XP.
  4. Windows 2000/XP will have no problems formatting a 2 TB Raid 1 (Mirrored) drive in the MBR format. However, it will not be able to convert that 2 TB RAID 1 drive to a 4 TB RAID 0 drive.
  5. Likewise, Windows 2000/XP will not be able to convert a 4 TB RAID 0 external drive to a 2 TB RAID 1 drive. You will need the use of a computer running Windows Vista (using a GPT partition), XP (64-bit), or Mac 10.4/10.5 to convert the drive from 4 TB RAID 0 to 2 TB RAID 1.
  6. Windows 2000/XP will not be able to convert any 2 TB, or smaller, GUID partitioned drive to an MBR partition through Window’s Disk Management. This will require a utility, such as DLG Diagnostics, that can write zeros to the drive so it can be partitioned and formatted through Windows 2000/XP.