Can’t extend the drive in Windows 10/11? Here’s what to do

by Tashreef Shareef
Tashreef Shareef
Tashreef Shareef
Windows & Software Expert
Tashreef Shareef is a software developer turned tech writer. He discovered his interest in technology after reading a tech magazine accidentally. Now he writes about everything tech from... read more
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By default, most of the user install their programs (games and applications) on the system (C:) drive. If you use too many applications, the drive will run out of free space in no time. To increase the C: drive size, you can use the Disk Management tool to extend the volume.

However, at times when users try to extend the volume using the Disk Management tool, some of them noticed that the Extend Volume option is greyed out and they were unable to extend the drive. Here is how to fix the greyed out Extend Volume option in Windows 10.

If you’re unable to extend a drive in Windows 10, check these steps

  1. Use AOMEI Partition Assistant to Merge Partition
  2. Create Qualified Unallocated Space

1. Use AOMEI Partition Assistant to Merge Partition

AOMEI is a free partition assistant tool that allows you to extend and shrink the disk partition without having to delete any other partition. This option is better than the second method, where you would have to delete the D: drive to extend the C: drive volume. Here is how to do it.

  1. Download and install the AOMEI Partition Assistant.
  2. After the installation is overrun AOMEI Partition Assistant
    AOMEI Partition - Merge Partition
  3. Right-click on the C: Drive and select Merge Partitions.
  4. In the Merger Partitions window, select the Unallocated space.
  5. Click OK to proceed.
  6. Next, preview the action. Click Apply and Proceed to save the changes.

What to do if you don’t have unallocated space to extend the volume?

AOMEI Partition Assistant allows you to allocate free space from the D: drive to C: drive without deleting the partition. Here is how to do it.

  1. Launch AOMEI Partition Assistant.
  2. Right-click on the D: > drive and select the “Allocate Free Space” option.
    AOMEI Partition - Allocate Free Space
  3. In the Allocate Free Space interface, select amount of space you want to allocate to the C: drive.
    AOMEI Partition - Allocate Free Space- D to C
  4. Make sure you select the C: drive as the target drive for allocating the space.
  5. Click OK to proceed.
  6. Preview the space allocation and click on Apply and Proceed to save the changes.

2. Create Qualified Unallocated Space

The reason why the Extend Volume option is greyed out in the disk management tool is because of the unallocated space is not right contiguous to the C drive. To make it work, you need to put the unallocated space right next to the C drive and then extend the volume. Here is how to do it.

To do this, you need to delete the partition next to the C: drive that is D: drive in most of the cases. So, begin with taking the backup of your data in the D: > drive. Once the backup is ready, proceed with the following steps.

  1. In the Cortana/search bar, type Create and format and open Create and Format hard disk partitions.
    Disk Management tool - Delete E Drive
  2. Right-click on the D:> drive (E: in this case) and select Delete volume.  (The D drive here is representational. If you have any other letter drive between the C drive and unallocated space, you need to delete that volume).
  3. A pop-up window will appear asking you to confirm the Delete Volume action. Click on Yes.

Now, you will see the partition next to the C: drive is unallocated. You can easily extend the C: volume without any problem.

  1. Right-click on the C: > drive and select Extend Volume.
  2. Proceed with the on-screen instruction to increase the C: drive size.

Wrap Up!

These are the two ways to extend the volume for C: drive and fix the Extend Volume greyed out in the disk management tool.

I prefer the first method as it is easier, offers more options, and it does not require deleting any partitions to extend the C: drive. However, if you don’t want to install third-party software to extend the drive, you can go with the second method to the same effect.


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