Diskpart Cannot Extend Partitions beyond 2TB - How to Solve

February 14, 2019

Irritated by Diskpart cannot extend partitions beyond the 2TB issue? No need to worry from now on. This article will provide you with effective and easy solutions to extending partitions over 2TB on large MBR disks.

The Symptom

While using Diskpart utility to manage a hard drive beyond 2TB, you may find out that Diskpart cannot extend partitions beyond the 2TB with the Virtual Disk Service errors:

Only the first 2TB are usable on large MBR disks. Cannot create partitions beyond the 2TB mark, nor convert the disk to dynamic.

Service Error

It may also fail with the following error message:

The volume cannot be extended because the file system does not support it.

The Cause

This error is quite clear as the message stated. MBR (Master Boot Record) disks support the maximum disk space up to 2TB, and four primary partitions, meaning the storage space beyond 2tb on a MBR disk will be unusable. You can convert to GPT (GUID Partition Table) disk, which can make use of disks larger than 2TB hard drive.

FAT32 file system limits the maximum partition size to 2TB. If your partition is using FAT 32 file system, Diskpart cannot extend partitions beyond the 2TB. Fortunately, Microsoft introduced a new file system NTFS in 1993, which allows you to create much larger partitions. If this is the case, you only need to reformat it as NTFS. While creating or formatting a NTFS partition, the allocation unit size also needs your concern, because it determines the maximum partition size of NTFS partitions. The maximum size of NTFS partition = allocation unit size * (2^32 -1). You can check the partition table and file system of the disk, and then choose the solution to solve it.

Solution 1: convert MBR to GPT disk without data loss

If your hard drive is an MBR disk, you can use a freeware to convert it to GPT disk. AOMEI Partition Assistant Standard, free partition manager software, allows you to convert disk to GPT without affecting the data on that disk. If you want to convert the system disk, you will need AOMEI Partition Assistant Professional and make sure your motherboard support EFI/UEFI boot mode. Let’s see how it works:

1. Download the free software. Install and launch it.

2. Right click the disk and select Convert to GPT.

Convert MBR to GPT

3. Click Apply to perform the operation.

Convert to GPT

Apply Convert MBR to GPT

Then you should be able to extend partitions beyond the 2tb with Diskpart, and you can also use AOMEI Partition Assistant to extend partition.

To convert disk from MBR to GPT, you can also use command “convert gpt” in Diskpart, but this only works when the disk must be completely empty without any data partitions or volumes. You can use “delete disk [noerr][override]” command to delete the disk before the conversion. Windows built-in utility Disk Management is also available to convert a completely empty disk (shown as unallocated space) to GPT disk. Either using Diskpart or Disk Management requires you to erase the hard drive, backup your hard drive before trying. Note that this only works with 64 bit OS.

Solution 2: convert FAT32 to NTFS without data loss

If you still cannot extend 2TB partition after converting the disk to GPT disk, you may check the partition file system. Usually, to convert FAT32 to NTFS you need to reformat the partition or volume as a result all the data on it will be deleted. Luckily, the powerful tool AOMEI Partition Assistant Pro allows you to convert FAT32 to NTFS without data loss.

To convert FAT32 to NTFS:

1. Download AOMEI Partition Assistant Pro Demo Version and run it. Then click All Tools -> NTFS to FAT32 Converter.

NTFS to FAT32 Converter

2. Select FAT32 to NTFS.


3. The program will list the partitions formatted with FAT32. Select the partition you want to convert and click Next and Proceed to start the conversion.

FAT32 Partitions

Proceed FAT32 to NTFS

After these two steps, the problem that diskpart cannot extend partitions beyond the 2tb should be fixed. Providing many useful features, AOMEI Partition Assistant can be used to make bootable media, Migrate OS to SSD, resize partition, and more. Available in multiple versions, AOMEI Partition Assistant works with Windows 10/8.1/8/7/XP/Vista and Windows Server 2012/2008R2/2008/2003.