Enable Extend Volume option in Disk Management for C drive

By Andy, Updated on: September 26, 2024

When system C drive is running out of space in Windows XP and Server 2003, if you don't want to use 3rd-party software, you have to back up, recreate partitions and restore everything. From Windows 7 and Server 2008, Microsoft added new "Shrink Volume" and "Extend Volume" functions to help change partition size without losing data. However many people feedback that Extend Volume greyed out after shrinking volume D, so they cannot extend C drive. This article introduces why Extend Volume is disabled and how to enable Extend Volume option in Disk Management.

Why Extend Volume is disabled in Disk Management?

There are many reasons why Extend Volume doesn't work, open your Disk Management and find out your disk partition configuration, then you'll know the corresponding reason in your computer.

  1. No contiguous unallocated space on the right
    Extend Volume can only merge unallocated space to the left contiguous partition. This is the reason why Disk Management cannot extend C drive and E after shrinking D.
  2. Only NTFS is supported
    Extend Volume can only extend partition formatted with NTFS file system, FAT32 and other types of partitions can't be extended even if there's right contiguous unallocated space.
  3. Restriction between primary and logical partitions
    Unlike primary partition, the disk space of logical drive will be changed to Free after deleting, this Free space can't be extended to any primary partition. Likewise, unallocated space can't be extended to any logical drives. This is the reason why Extend Volume still greyed out after deleting the right contiguous partition.
  4. Limitation of MBR disk
    The maximum size of a partition in MBR disk is 2TB, therefore, if C drive or other partition is 2TB, Disk Management cannot extend it even if there's right contiguous unallocated space.

How to enable Extend Volume for C drive

In most of personal computers and Windows servers, system C drive is formatted with NTFS by default. Therefore, if your system disk is GPT, no adjacent unallocated space is the most possible reason why extend C drive greyed out. If you use MBR disk, check if the right adjacent partition (D) is a logical drive.

If you shrunk drive D but extend volume greyed out for C drive in Disk Management, there are 2 solutions with native tool and third party software.

Solution 1: delete the right contiguous partition

Note: the right contiguous partition D must be primary, do not delete D if you installed programs or Windows services into it.

If you can delete the adjacent partition D, its disk space will be converted to unallocated and behind C drive. Follow the steps to enable Extend Volume for C drive in Disk Management:

  1. Back up or transfer all files in drive D to other place.
  2. Open Disk Management, right click D: and select Delete Volume.
  3. Right click C: drive and select Extend Volume.
  4. In the pop-up Extend Volume Wizard window, simply click Next till Finish.

Solution 2: move partition D to the right

If you cannot delete D or if it is a logical drive, Disk Management is useless. You need to run third party software to move partition D to the right, unallocated space will be moved to the left at the same time.

How to enable Extend Volume option for C drive:

  1. Download and run NIUBI Partition Editor, right click drive D and select "Resize/Move Volume", drag the middle  of D drive towards right in the pop-up window. Then unallocated space will be moved to the left side, Extend Volume will be enabled for C drive in Disk Management.
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right in the pop-up window. Then unallocated space will be merged to C drive.
  3. Click Apply on top left to execute.

There is free edition for Windows 11/10/8/7/Vista/XP home computer users.

Video guide

How to enable Extend Volume option for D and other volume

To data volume, if it is a FAT32 partition, Disk Management cannot help you. When resizing partitions with NIUBI Partition Editor, there's no difference to NTFS or FAT32 partition, primary or logical partition. If Extend Volume greyed out because your MBR disk is 2TB+, convert it to GPT with NIUBI, follow the steps in the video:

How to shrink and extend partition:

Video guide

How to convert MBR disk to GPT:

Video guide

Besides shrinking, moving and extending partitions, NIUBI Partition Editor helps do many other disk and partition operations. Better than other tools, it has innovative 1-Second Rollback, Virtual Mode, Cancel-at-will and Hot Clone technologies to protect system and data. In addition, it is 30% to 300% faster because of the advanced file-moving algorithm.

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