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4 Easy Solutions to Fix 'Unable to Extend C Drive' in Windows 11

Are you Unable to Extend C Drive in Windows 11 and looking to fix your problem? Consider yourself lucky! Here, we have four excellent solutions that can help you do so. Read more.

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Updated by Tracy King on Jul 20, 2023

Workable Solutions Step-by-step Troubleshooting
Option 1. Delete Volume with Disk Management Step 1: Open the Win+X menu and choose Disk Management by clicking or tapping on it (diskmgmt. msc)...Full steps
Option 2. Shrink Volume with Disk Management Step 1: In the Windows search box, type and search for Computer Management and select Run as administrator...Full steps
Option 3. Merge Non-Adjacent Unallocated Space with EaseUS Partition Master Step 1. Right-click the partition that next to the unallocated space, select "Resize/Move"; Step 2. Put the mouse...Full steps
Option 4. Allocate Space from Another Disk with EaseUS Partition Master Step 1. Right-click on the D: partition with enough free space and select "Allocate Space"; Step 2. Select the target...Full steps


Regardless of the Windows version or the device you use, you've probably seen that PCs slow down with time if you're a Windows user. That's because, as you keep using the gadget, you'll accumulate more data and files. You'll often find yourself in a scenario where you have plenty of room in other partitions, but you keep seeing pop-ups claiming "you're running out of space", even if you have plenty of capacity in other dividers.

Your computer's performance begins to deteriorate, apps become sluggish, and you're unable to increase the space of your hard disk. Let's look at the reasons you are Unable to Extend C Drive in Windows 11. Then, we will look at the solutions with which you can easily solve this problem!

Why Can't I Extend My C Partition?

You shouldn't be concerned if you cannot extend a volume. For example, you cannot expand a volume in the C drive. Open Windows Disk Management and look at the condition of your disk partition and the explanations given in the section below.

  • Windows cannot enlarge if the partition is formatted in FAT or another type.
  • There is no continuous unallocated space or free space available in the area behind the partition you wish to expand.
  • No unallocated space exists on your computer's hard disk.

The Extend Volume option in Disk Management is only available for partitions formatted as RAW or NTFS. Windows PCs do not support the expansion of FAT or other file system partitions.

  • The partition capacity has hit the 2TB limit when using an MBR drive.
  • In any case, Windows will not allow you to enlarge the main partition by using unallocated space in an extended partition or vice versa.

You can learn how to check total hard disk space in windows 10 in this link.

Having determined the reason for the greyed-out status of Extend Volume, we must determine how to activate it or raise the partition size in certain cases.

How to Fix "Unable to Extend C Drive"?

This part of our guide will guide users about the methods they can adopt to fix their Extend C Drive problem. However, before we do that, the users must know about two situations:

  1. 1. No Unallocated space - if that's the issue you're facing with your disk, go for option 1 and option 2 to delete or shrink the partition on disk management. However, bear in mind that this can potentially lead to data loss.
  2. 2. Has Non-Adjacent Unallocated Space - if you have a non-adjacent unallocated space, it's best to use third-party software, as explained below in option 3.

Option 1. Delete Volume on Disk Management

When you remove a volume or partition from a disk, the previously reserved space for that volume or partition becomes available on the drive. You may then extend another volume/partition on the same disk into this unallocated space to add the unallocated space to the volume/partition that was previously extended.

Step 1: Open the Win+X menu and choose Disk Management by clicking or tapping on it (diskmgmt. msc).

Step 2: When you right-click or press and hold on a partition/volume (for example, "G"), choose to Delete Volume from the context menu that appears.

delete volume

Step 3: To confirm, choose Yes from the drop-down menu.

Note: The volume/partition will now be erased, and the remaining space on the drive will be shown as Unallocated space.

disk management with unallocated space

Option 2. Shrink Volume with Disk Management

It is possible to produce fresh disk space from an existing disk by shrinking the volume, and this new space will be an unallocated area.

If you realize that you need an extra partition but do not have any more drives available, you may follow the procedures outlined below to create one on your computer.

Note: Keep in mind that shrinking the partition may cause the data to be lost if the current partition includes data. We strongly advise that you make a backup of your data before reducing the partition.

Step 1: In the Windows search box, type and search for Computer Management and select Run as administrator.

computer management and run as administrator

Step 2: Select Disk Management from the Computer Management menu.

select disk management from computer management

Step 3: In Disk Management, right-click the current volume on which you wish to create an extra partition and pick Shrink Volume from the context menu.

shrink volume of disk

Note: Reduce volume will compute the maximum space that can be reduced automatically.

Step 4: Alternatively, input the size you wish to reduce and click Shrink volume.

shrink disk volume

Step 5: An unallocated area will be generated in Disk Management after the shrink has been finished. You may utilize the unallocated region to build a new partition after being established.

unallocated space in disk management

Option 3. Merge Non-Adjacent Unallocated Space

Disk Management is not without its flaws, and third-party software such as EaseUS Partition Master is intended to compensate. It is compatible with all Windows systems and offers users extra disk management tools.

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Among the features that distinguish it as a must-have tool is the ability to "Migrate OS", "resize/move", "Wipe", "Hide", and "Convert between MBR/GPT or Basic/Dynamic", among others. The argument is that, rather than removing all connected partitions and assigning the vacant space into a single partition, you may utilize the "Merge" option to combine two partitions into a single one.

Users face three frequent scenarios when attempting to combine non-adjacent partitions. EaseUS Partition Master may be used in any situation. Installing and launching the program on your PC is simple. We'll go through each stage in detail one by one as we go along.

Main Features of EaseUS Partition Master:

  • This online converter converts from MBR to GPT or GPT to MBR.
  • Partitions may be merged without any data being lost.
  • Transfer the operating system to a solid-state drive.
  • Partitions may be created, formatted, and deleted.

Steps to Merge:

Step 1. Select the partition next to the unallocated space, select "Resize/Move".

resize unallocated space

Step 2. Put the mouse on the partition and drag it to the left or right to move the unallocated space.

resize unallocated space 2

You can repeat Step 1 and 2 to move the unallocated space to the desired location.

Move unallocated space to a desired position

Step 3. Click "Execute Task" and "Apply", it will execute the operations to add the unallocated space into the target partition eventually.

resize unallocated space 5

Option 4. Allocate Space from Another Disk

"Allocate Space" is a function in EaseUS Partition Master that allows you to allocate disk space. You may use it to assign the unused space of a specified disk to some other disk on the same hard drive without deleting the space from the chosen partition.

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Steps to Allocate Space:

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


If there is no accessible unallocated space on the C drive in Windows 10/11 Disk Management, you will be unable to expand the disk. It is okay to delete a partition to get a sufficient amount of unallocated space. However, the whole procedure is time-consuming. As a result, it is recommended that you choose one of the remedies listed above.

If there is unallocated or unoccupied space, choose between option 1 and 2. Alternatively, if there is no available space, you may use option 3. If the whole system drive is too tiny, you can transfer it to a bigger disk using EaseUS Partition Master, allowing you to replace the disk without having to reinstall Windows or other apps.

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About the Author

Updated by Tracy King

Tracy joined in EaseUS in 2013 and has been working with EaseUS content team for over 10 years. Being enthusiastic in computing and technology, she writes tech how-to articles and share technical solutions to resolve Windows & Mac data recovery, data backup, partition management, data transfer, Windows update issues, etc.

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