"Hi, I want to extend my drive C volume, but it does not allow me to extend. The "Extend volume" option is grey, so I cannot click it."

This is a real user case from Microsoft Community. Are you having this error that the Extend Volume greyed out while trying to increase C drive or other partition space on Windows 11/10? On this page, EaseUS will discuss why the Extend Volume Option is greyed out and how to fix the "can't extend volume" error on Windows 11/10/8/7 and even Windows Server computers.

Your Most Reliable Tool for Fixing "C Drive Extend Volume Greyed Out"

In order to help you out of the "Extend Volume Greyed Out" error and successfully increase partition size, we recommend you try a reliable tool for extending volume - EaseUS Partition Master Professional.

- EaseUS Partition Master -

Your Smart Windows 11 Update Disk Manager

  • MBR to GPT Converter, Make Disk Ready for Windows 11.
  • Migrate Windows 11 to New SSD in 1-Click.
  • Handy to Extend or Combine Partitions in Windows 11.
  • Clone and Upgrade Disks without Data Loss.
Free DownloadWindows 11/10/8/7

Its Resize/Move and Allocate Space feature will effectively fix all the issues, helping you effectively extend volume on Windows 11/10/8/7.

💡Read Also: Fix Unable to Extend C Drive

Situation 1. No Unallocated Space

When your hard disk doesn't have unallocated space, you can't extend a volume. You can either apply Disk Management or apply EaseUS Partition Master for help.

You can follow either way to enlarge your target partition on Windows 11/10/8/7 now.

#1. Using EaseUS Partition Master

EaseUS Partition Master, with its Allocate Space feature, enables you to move free space from other partitions flexibly to extend a target volume.

Free Download 

Windows 11/10/8/7100% Secure

Step 1. Right-click on the D: partition with enough free space and select "Allocate Space".

Select partition to allocate space

Step 2. Select the target partition - C: drive and drag the partition panel rightward to add the free space from D: drive to C: drive. Then click "OK" to confirm.

Allocate space to extend partition

Step 3. Click the "Execute Task" button and click "Apply" to start the process of moving free space from D: drive to C: drive.

finish extending partition

#2. Make Unallocated Space and Extend Volume via Disk Management

Note that if you can't extend C drive space, you can also enable Extend Volume in the system partition with the same steps below: 

Step 1. Make Free or Unallocated Space behind the Target Volume 

If you don't have free or unallocated space on the computer drive, you must first delete an empty or useless partition(except the recovery partition) or shrink a partition to leave free/unallocated space next to the target volume.

  1. 1. Press the Windows + X keys and click "Disk Management."
  2. 2. Right-click an empty partition next to the target volume and select "Delete Volume." Click "OK".

Delete volume to free up space

  • 3. You can also right-click a neighbor partition with enough free space to select "Shrink volume."
  • 4. Specify the amount of space to shrink. Click "Shrink" and "OK" to confirm.

Shrink volume to free up space

You are now good to go follow the steps below to enlarge a hard disk partition without the "can't extend volume" error any longer.

Step 2. Enable Extend Volume, Increase Partition Size

  1. 1. In Disk Management, right-click the target partition you want to extend.
  2. 2. Select "Extend Volume" and adjust the size you want to add to the target volume.
  3. 3. Click "OK" to confirm.

Extend Volume after leaving up enough unallocated space

Situation 2. Without Adjacent Unallocated Space

If you have unallocated space on your disk, but it's not next to your target volume, the Extend Volume option will display as greyed out in Disk Management. You can use EaseUS Partition Master to extend the system partition with its Resize/Move feature.

Free Download 

Windows 11/10/8/7100% Secure

Step 1. Locate the Target Partition.

Go to Partition Manager, locate the target partition and select "Resize/Move".

Select target partition to extend

Step 2. Extend the Target Partition.

Drag the partition panel rightward or leftward to add the unallocated space into your current partition and click "OK" to confirm.

choose another drive to allocate space

Extra Option: Get Space from Another Drive

If there is not enough unallocated space on your disk, right-click on a big partition with enough free space, select "Allocate space".

Then select the target partition that you want to extend at the allocate space to column.

choose another drive to allocate space

Step 3. Execute Operations to Extend Partition.

Drag the dots of the target partition into the unallocated space and click "OK".

finish extending partition

Then Click the "Execute Task" button and click "Apply" to keep all the changes. 

Situation 3. When Partition Is FAT or Other Format

Due to the Windows limitation, you can't directly use Disk Management to extend FAT, exFAT, and EXT partitions. Here, you have two options to fix this error:

  1. #1. Extend FAT or Other Format Partition Using EaseUS Partition Master

EaseUS Partition Master breaks the limit in Windows PC, and you can directly follow the steps in Method 1 or Method 2 to extend your target partition with ease.

  1. #2. Convert FAT to NTFS and Extend Partition in Disk Management

To convert the FAT partition to NTFS, you'll need to format or delete the partition, which will cause file loss. Therefore, we don't recommend you try this method. It's time-consuming and risky.

Situation 4. With Space on Extended Partition or Vice Versa

Windows also doesn't allow you to extend a primary partition with unallocated space in an extended partition, so it is to extend a logical partition with space in a primary partition. 

Therefore, to fix this issue and extend a volume, you'll need to turn to third-party partition manager software for help. EaseUS Partition Master can help. 

Free Download 

Windows 11/10/8/7100% Secure

Video Tutorial: Extend and Partition Hard Drive

The following video tutorial shows how to partition a hard disk on Windows 10, and you can learn how to extend volume in this video:

Situation 5. When MBR Partition Reaches 2 TB

This is a rare case but happens sometimes on an MBR partition. If you create a single volume that reaches 2TB capacity, you can't continue extending the partition. Then, the Extend Volume Option will grey out.

In this case, you can convert the MBR disk to a GPT disk to break the limit. We don't suggest you use Disk Management to execute the operation, as it requires deleting all partitions to convert a disk. 

EaseUS Partition Master, with its disk conversion feature, will do the work. You may refer to Convert MBR to GPT for help.

Also Read: How to Partition A Hard Drive in Windows 10

Video Tutorial - Extend Volume Greyed Out In Windows 10

The video tutorial released by Sandeep Singh shows how to fix the extend volume option greyed out in Windows 10 while using Disk Management.

Manual way to create unallocated space next to C drive in Disk Management - 0:34 - 3:33

If you think these methods work for you, you can share them to help more friends.


Why Is Extend Volume Greyed Out

If you can't extend volume, like you cannot extend volume in C drive, don't worry. Open Windows Disk Management, check the state of your disk partition, and the listed reasons below. You'll find why is the Extend Volume option greyed out on your computer:

  • There is no unallocated space on your hard drive.
  • There is no contiguous unallocated space or free space behind the partition you want to extend. 
  • Windows can't extend a FAT or other format partition.

The Extend Volume option in Disk Management only works on a RAW or NTFS partition. You can't extend FAT or other format partitions on a Windows PC.

  • Windows can't extend a primary partition with unallocated space in an extended partition or vice versa.
  • The partition capacity has reached the 2TB limit on the MBR disk.


On this page, we offer 6 reliable methods to help you fix the "Extend Volume greyed out" error and extend partitions successfully, no matter whether you have free or unallocated space on your computer hard drive.

If you prefer a reliable & free tool to extend partitions, EaseUS Partition Master Free Edition is more reliable as it doesn't require deleting the partition even if you don't have unallocated space. Also, no data loss will occur by extending volume using this free partition tool.

Free Download 

Windows 11/10/8/7100% Secure

Can't Extend C Drive FAQs

1. Why can't I extend partition C in Windows 10 (why is extend volume greyed out)?

Does Disk Management extend volume greyed out? Unallocated space beside the C drive can cause an extended volume greyed-out issue. If you are trying to extend the c drive, a free partitioning tool can manage the partition.

2. How do I fix the extended volume greyed out?

The best way is to create an unallocated disk space to the right of the target partition. To make unallocated space, you can delete the adjacent volume (data loss!). Or try EaseUS Partition Master to manage and extend disk space freely.

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Updated by Oliver

Oliver is an EaseUS professional writer who dares explore new areas. With a passion for solving tech issues with straightforward guides for common users, Oliver keeps honing his writing craft by developing in-depth solutions for disk and partition management, computer boot-up issues, file transfer, etc.

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Written by Brithny

Brithny is a technology enthusiast, aiming to make readers' tech lives easy and enjoyable. She loves exploring new technologies and writing technical how-to tips. In her spare time, she loves sharing things about her game experience on Facebook or Twitter.

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