4TB Hard Drive Only Shows 2TB Windows | Why & How to Fix

Is your 4TB hard drive only showing 2TB in Windows? You're likely using the outdated MBR partition scheme. This guide explains the root cause, helps you check your system settings, and walks you through safe, beginner-friendly ways to convert to GPT—no data loss required.

• Method 1. Convert the 4TB Disk From MBR to GPT - Work Best
• Method 2. Check BIOS Settings - Regular Check and Adjustment
• Method 3. Check for Bad Sectors and File System Errors - Real Cases

Have you installed a new 4TB HDD or SSD only to find that Windows 11 recognizes just 2TB? You're not alone. A 4TB hard drive may only show 2TB of available space due to its partition style being Master Boot Record (MBR), which has a 2TB size limit. To utilize the full 4TB capacity, the drive needs to be converted to GUID Partition Table (GPT) format.

To fix 4TB hard drive or SSD showing only 2TB error, I explored many real cases from Reddit and Microsoft Support, including the main causes and the possible solutions. First, let's go through the reasons why the 4TB hard drive only shows 2TB.

Why Does My 4TB Hard Drive Only Show 2TB

Why are only the first 2TB usable on a 4TB hard drive or SSD? This problem is usually caused by the use of the MBR (Master Boot Record) partitioning style, which has a built-in size limitation of 2TB. Drives larger than that need to use GPT (GUID Partition Table) to access their full capacity. There is a list for you to learn all of the causes of hard drive not showing full capacity:

1️⃣MBR Partition Limit: MBR disks can't recognize space beyond 2TB. (The technical root of this error) This is why only the first 2 TB are usable on a large mbr disk. (This is one infographic to master MBR to GPT)

One click to convert MBR to GPT to fix the current error.

2️⃣Legacy BIOS: Older systems using Legacy BIOS instead of UEFI won't support GPT boot disks.

3️⃣File System Formatting Issues: Using FAT32 or incorrect formatting may result in capacity issues.

4️⃣Bad Sectors Accumulation: Too many bad sectors make the hard disk drive unable to read correctly and show the wrong capacity.

So how do I get my 4TB hard drive to show its full capacity? You need to convert the MBR disk to GPT style or update the outdated firmware to fix this error. We offer detailed instructions in the next part, and feel free to share this post to help more users.

4TB Hard Drive Only Shows 2TB? How to Fix?

Before you fix it, figure out what's going wrong. Here's a quick checklist to help diagnose the issue:

• Check Disk Properties: Right-click Start > Disk Management > Right-click the disk > Properties > Volumes tab > Check Partition Style (MBR or GPT).
• See If Unallocated Space Exists: If only 2TB is shown as usable, you may have 2TB+ in unallocated space.
• Check Boot Mode: Is your PC set to UEFI or Legacy BIOS? Windows 11 requires UEFI + GPT.
• Check File System Format: If the disk was formatted using FAT32, the OS may limit usable capacity. NTFS or exFAT is recommended.
• Verify Windows Version: Windows 7/8 may not fully support GPT booting or drives over 2TB without updates.

If your drive is using MBR and there's unallocated space, you'll need to convert it to GPT. 

Method 1. Convert the 4TB Disk From MBR to GPT

Continue to this section to choose the solution that fits your situation best.

EaseUS Partition Master can help convert MBR to GPT without losing data to fix the disk that only shows a 2TB error. Disk Management and DiskPart may cause data loss. If the 4TB hard drive is your boot drive, ensure you use reliable third-party software, such as EaseUS Partition Master, as Windows' built-in tools don't support converting a system disk.

Guide 1. Convert 4TB Drive to GPT with EaseUS Partition Master

EaseUS Partition Master can convert a hard drive from MBR to GPT without data loss, and it supports converting a system MBR disk. For beginners, it's easier to use than Disk Management and DiskPart.

• Data Loss: No, convert MBR to GPT without losing any data
• Support System Disk: Yes, support converting the system disk
• Easy to Use: Yes, clear interface and doesn't require any command lines
• Compatibility: Support Windows 11/10/8/7

How to use EaseUS Partition Master to convert MBR to GPT and fix 4TB hard drive or SSD only showing 2TB? Here are the steps:

Step 1. Install and launch EaseUS Partition Master on your computer.

Step 2. Open the Disk Converter tab, select "MBR => GPT" and click "Next" to continue.

Step 3. Choose the target MBR disk, and click "Convert" to start the conversion.

To fix only the first 2TBof a large disk is usable, use EaseUS Partition Master and convert MBR to GPT now.

Guide 2. Convert 4TB Drive to GPT with Diskpart

• Complex Level: Complex
• Best for: Advanced users and professionals
• Benefits: Free to use;
• Drawbacks: Requesting to delete partitions and data loss.

Similar to Windows Disk Management, Diskpart enables you to convert an empty MBR disk to GPT via Command Prompt command lines. If you need to convert an already partitioned MBR disk, first back up the file and delete all the partitions.

Step 1. Press the Windows+R keys, type CMD, and press Enter to open the command prompt.

Step 2. Type diskpart and hit Enter. Type the following commands in order; remember to press Enter after you input each one.

• list disk 
• select disk 1 (1 means the drive letter, replace it with your 4TB drive letter)
• clean (clear all partitions on the selected disk)
• convert gpt

You can see the 4TB hard drive has been turned into the GPT style. 

After the MBR to GPT conversion, you can create partitions to restore the 4TB hard drive to its full capacity. 

Steps to create new partitions after the MBR to GPT conversion (Optional based on your needs):

• select disk 1
• create partition primary size=1024 (Replace 1024 with the correct number you want in MB)
• exit

Share this guide to help more users to fix 4TB hard drive showing the wrong capacity.

Guide 3. Convert MBR to GPT Using Disk Management

• Complex Level: Medium
• Best for: Experienced users and advanced administrators
• Benefits: Free to use;
• Drawbacks: Requesting the deletion of partitions causes data loss during the conversion.

Converting to GPT Disk option in Disk Management only works when your disk is empty, or you will see the Convert to GPT Disk greyed out. If there are files or partitions on the 4TB hard drive, you need to delete all the existing volumes first. So, back up your important files if necessary.

Step 1. Right-click on the Windows button, and select to open Disk Management.

Step 2. Find the hard drive that shows the wrong capacity. Right-click the volumes on the disk and choose "Delete Volume...".

NOTICE: If you accidentally deleted a volume in Disk Management, see how to recover lost or deleted hard disk partition. 

Step 3. When the hard drive shows as unallocated space, right-click the disk and choose "Convert to GPT Disk".

Method 2. Check BIOS Settings

If your drive still shows only 2TB after converting to GPT, your system may be using Legacy BIOS mode.

Here is how to check BIOS settings to fix only the first 2TB usable errors:

• Reboot and enter BIOS setup (usually F2 or DEL during startup)
• Look for Boot Mode and switch from Legacy to UEFI.
• Save changes and reboot.

Also, update BIOS firmware if necessary; Windows 11 requires UEFI + GPT to function correctly on the system drive.

• Visit your motherboard or computer manufacturer's official support website.
• Locate the correct BIOS update by entering your exact model number.
• Carefully read the instructions provided with the BIOS file.
• Download and apply the update using the provided utility (usually a Windows-based program or USB flash update tool).

Method 3. Check for Bad Sectors and File System Errors

In rare cases, a drive may not show its full capacity due to hardware-level issues like accumulated bad sectors or improper formatting during a previous setup. These problems can cause the operating system to misreport available space or prevent GPT initialization.

• Run a Disk Surface Test: Use a disk management tool (like EaseUS Partition Master or CHKDSK in Windows) to scan the drive for bad sectors. If bad blocks are found, data recovery and drive replacement may be necessary.
• Fully Reformat the Drive: If the formatting was previously interrupted or performed with third-party tools that are incompatible, consider reformatting and reinitializing the disk as GPT using trusted software.

Bonus Tip: Failed to Convert MBR to GPT?

Sometimes, when you try to convert an MBR disk to GPT — especially using Disk Management or DiskPart — you might run into errors like:

"The operation is not allowed on disks containing system partitions." - From r/techsupport

"Virtual Disk Service error: The specified disk is not empty." - From r/buildapc

These issues can prevent you from converting your disk and fully using the 4TB capacity. Here's why this happens and how to fix it.

Why the Conversion Might Fail

• The disk contains system or boot partitions: Windows won't allow converting a system disk while it's running.
• The disk isn't empty: DiskPart requires all partitions to be deleted before conversion.
• The disk is in use: Background services or programs might be locking it.
• There are partition errors or bad sectors: These can block the process.
• You're using an older version of Windows: Some systems lack full GPT support.

Solutions to Fix the Problem

With EaseUS Partition Master, you can convert MBR to GPT directly — no data loss, no formatting required. This is the safest and easiest solution, even if the disk contains the system or boot partition.

Conclusion

If your 4TB drive only shows 2TB, don't worry—it's a fixable issue. Typically, the MBR limit is the root cause, and the GPT style is the solution.
By understanding the limitations of MBR and switching to GPT using a reliable tool like EaseUS Partition Master, you can unlock the full capacity of your storage device quickly and without risk. Stop wasting disk space. Reclaim your full 4TB now!

FAQs About Windows 11 Maximum Disk Size and 4TB Drive Not Showing Full Capacity

If you also have any of the following frequently asked questions about 4TB hard drives only showing 2TB, find solutions here.

What is the Windows 11 maximum hard drive size?

Windows 11 itself doesn't impose a strict limit. The real constraint comes from the partition scheme: MBR supports up to 2TB, while GPT can handle drives up to 9.4ZB. As long as you're using GPT with NTFS, current drive sizes won't be a problem.

Why is my 4TB SSD only showing 2TB?

This usually means the drive is partitioned using MBR, which only supports up to 2TB. To access the full capacity, convert the disk to GPT to solve this error.

Will this work on Windows 11?

Yes. Windows 11 not only supports GPT and large drives, but also requires GPT for boot drives. All the methods listed in this guide are compatible with Windows 11.

My BIOS doesn't support UEFI. Can I still use 4TB drives?

Yes, but you may be limited to 2TB unless you upgrade your BIOS or use the drive for non-boot purposes.