Wednesday, July 11, 2012

Overcoming the 2TB partition size limit in Windows 7

I recently acquired some Hitachi Deskstar 4TB hard drives that I wanted to use in a desktop system that would be running Win 7, however the motherboard did not support UEFI which means I could not boot from a GPT formatted partition (which would support partitions greater than 2TB).  Through some research and a lot of bashing my head on my desk, I cooked up this solution.

What you'll need:
  • o Drive larger than 2TB
  • o Acronis True Image 2012 Home Boot Disk (You're resourceful, go find it)
  • o Seagate Discwizard (download) *coveat - you must have a spare Seagate or Maxtor drive
  • o MiniTool Partiton Wizard (home version and boot disk are free) - OR - Parted Magic (open source)

  1. Install Win 7 on disc, allow setup to do its thing - OR - clone existing drive to >2TB disk
  2. Inside windows, install Seagate Discwizard *-You will need to physically connect to mobo or via usb adapter a Seagate or Maxtor drive for install to work
  3. Boot machine using Acronis boot disk
  4. Choose Tools and then select Extended Capacity Manager - follow prompts to extend capacity of system disc
  5. Now reboot into Windows
  6. Run Seagate Discwizard making sure a Seagate or Maxtor drive are connected to your machine
  7. Choose Add New Disc and locate the partition you just created.  In the Model Number column, you will see the model number of the drive preceded by AVD. 
  8. Click next -> Initialize disc in MBR layout -> Click next -> Double click gray status bar of unallocated drive -> Choose formatting options you desire (default settings are fine if you want to use the entire drive) - Click accept -> Click next -> Click proceed and let it do its thing

When Discwizard is done, your OS should recognize there is a new disc present and autorun it.  You can verify you've done everything right by looking at your disc layout in windows Disk Management.  You might see there is some extra space left over as unallocated space.  You can then use the partition tool of your choice to expand either the system partition or the newly created partition to use up this extra space.  Be aware, windows backup in Win 7 will not allow you to backup discs larger than 2TB - so if you're planning to use it for backups, don't expand your system disc past an acceptable limit.  I used MiniTool to accomplish this as it can do it from within Windows and did not require booting the machine off a boot disc, which is what Parted Magic does. 

If you've gotten this far and you're not quite sure what I'm saying, check out Part 1 and Part 2 of the videos listed in one of Seagate's Forums.  In this example, they use Discwizard for everything, but unless you're working with a Seagate drive as the >2TB drive, some of the steps won't work, ie: Discwizard won't allow you to extend the capacity of a non-seagate/maxtor drive, even if you have one attached to the system.  I've used this method on two separate machines now, one a fresh Win 7 install and the other a cloned drive from a smaller hard drive.  In both instances, I have had complete success with zero data loss.


  1. I tried this and I got step 5 but after reboot I get BOOTMGR is missing ;-( so did I miss something or is this BS?

    1. Would love to know I have (2) 4TB Hitachi drives now and well they are just 2tb for the time being or I guess I am looking at a upgrade.

    2. Travis: no bullshit. These are the steps I took to make this work. If you're seeing BOOTMGR is missing, you might be able to fix that with either the windows 7 install disk (go into repair when setup starts and allow it to examine your disk and try to fix the problem) or google around for how to use diskpart to repair BOOTMGR is missing errors. I've run into problems like this when breaking raid volumes off, but never after using a disk clone tool to expand partitions.


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