Windows operating system comes built-in with a basic but useful disk partition management tool, aptly named Disk Management, which provides various functionality to deal with the disks, partitions and volumes in Windows. One of the function is to extend or increase the size of a partition, called Extend Volume.

Extend Volume is useful when a partition is running out of space and there is free unallocated space on the hard disk. Extra disk space can be added to a partition or volume that has not enough disk space to save new files, install programs or perform updates.

However, Extend Volume function is not always available for all disk partitions or volumes. Sometimes, when you want to expand a partition or volume, you may notice that the Extend Volume option is grayed out and disabled, effectively prevents the disk partition to be expanded in size.

Extend Volume Grayed Out

If you attempt to extend the volume or partition size via DiskPart utility, you get the following error instead:

Virtual Disk Service error:
There is not enough usable space for this operation.

There Is Not Enough Usable Space for This Operation

The built-in disk partitioning tools of Windows only support extension of volume or partition if the unallocated disk space is not contiguously located after (to the right of) the partition to be expanding in size, or the partition is not of NTFS or RAW filesystem.

The only workaround to expand the partition or volume is this case is by using third-party partition editor which has more advanced features. Luckily there is many disk partitioning utilities that are available for free, and can perform the extending of partition on the fly without the need of reboot or boot from CD.

Here’s a few free disk partitioning software available:

Changing partitions or volumes may cause loss of data. BACKUP before performing any disk partitioning operation.

After installing any third-party disk partitioning tool, there are two approaches that you can take to extend a partition or volume:

  1. Extend the partition size directly.

    Extend Partition

  2. Move the partition so that the free unallocated disk space is located contiguously after the partition to be extended. Normally, this is done by moving the partitions that stand in between the target partition and free space away to the back or front.

    Move Partition

    Then, using Disk Management in Windows to perform the “Extend Volume”.

In most disk partitioning software, the change is not immediately done. Remember to apply the change when done with selecting the operation to perform to volumes or partitions.