Why 4TB hard drive only shows 2TB?

It is a common problem that 4TB (or 5TB, 6TB,etc) hard drive only shows 2TB, and the rest space is shown as an unallocated space in Disk Management. What’s worse, you can’t even use it to create volumes or partitions for data storage. At this moment, if you open Disk Management, you will find it is labeled as MBR disk.

There are 2 partition styles most commonly used to partition disk, MPR & GPT. They are different slightly in supported partition amounts, disk capacity, OS compatibility and boot mode. For example, GPT can support disk larger than 2TB but MBR partition style cannot. And this is why your 4TB hard drive only shows 2TB. So, to restore all the capacity of the hard drive, you need to convert the MBR disk to GPT disk. In the following content, let me walk you through how to perform such conversion.

How to fix “4TB Drive Only Shows 2TB” in Windows Servers? Convert 4TB drive to GPT with Diskpart There is a built-in tool called Diskpart, which can convert 4TB hard drive to GPT with several lines of command. Here are the detailed steps.

Note: this method need to clean your disk before converting, so if it is not a new hard drive or has important data on it, you need to backup your disk


  1. Press WIN+R, type CMD and press Enter to open the command prompt. Then, input diskpart and hit Enter.
  2. Type the following commands, remember press Enter after you input each one.
  • list disk
  • select disk n (n means the drive letter, replace it with your 4TB drive letter)
  • clean (clear all partitions on the selected disk)
  • convert gpt