You can decrease the space used by simple or spanned volumes by shrinking them into contiguous free space at the end of the volume. For example, if you discover that you need an additional partition but do not have additional disks, you can shrink the existing partition from the end of the volume to create new unallocated space that can then be used for a new partition.

When you shrink a partition, any ordinary files are automatically relocated on the disk to create the new unallocated space. There is no need to reformat the disk to shrink the partition.

Backup Operator or Administrator is the minimum membership required to complete the actions below.

Caution

If the partition is a raw partition (that is, one without a file system) that contains data (such as a database file), shrinking the partition may destroy the data.

Shrinking a simple or spanned volume

To shrink a simple or spanned volume using the Windows interface

  1. In Disk Management, right-click the simple or spanned volume you want to shrink.

  2. Click Shrink Volume….

  3. Follow the instructions on your screen.

Additional considerations

  • When you shrink a partition, unmovable files (for example, the page file or the shadow copy storage area) are not automatically relocated and you cannot decrease the allocated space beyond the point where the unmovable files are located. If you need to shrink the partition further, move the page file to another disk, delete the stored shadow copies, shrink the volume, and then move the page file back to the disk.

  • If the number of bad clusters detected by dynamic bad-cluster remapping is too great, you cannot shrink the partition. If this occurs, you should consider moving the data and replacing the disk.

    Do not use a block-level copy to transfer the data. This will also copy the bad sector table and the new disk will treat the same sectors as bad even though they are normal.

  • You can shrink simple and spanned dynamic disks, but not others.

To shrink a simple or spanned volume using a command line

  1. Open a command prompt and type diskpart.

  2. At the DISKPART prompt, type list volume. Make note of the number of the simple volume you want to shrink.

  3. At the DISKPART prompt, type select volume <volumenumber>. Selects the simple volume volumenumber you want to shrink.

  4. At the DISKPART prompt, type shrink [desired=<desiredsize>] [minimum=<minimumsize>]. Shrinks the selected volume to desiredsize in megabytes (MB) is possible, or to minimumsize if desiredsize is too large.

Value Description

list volume

Displays a list of basic and dynamic volumes on all disks.

select volume

Selects the specified volume, where volumenumber is the volume number, and gives it focus. If no volume is specified, the select command lists the current volume with focus. You can specify the volume by number, drive letter, or mount point path. On a basic disk, selecting a volume also gives the corresponding partition focus.

shrink

Shrinks the volume with focus to create unallocated space.

No data loss occurs. If the partition includes unmovable files (such as the page file or the shadow copy storage area), the volume will shrink to the point where the unmovable files are located.

desired= desiredsize

The amount of space, in megabytes (MB) to recover to the current partition.

minimum= minimumsize

The minimum amount of space, in megabytes (MB), to recover to the current partition. If you do not specify a desired or minimum size, the command will reclaim the maximum amount of space possible.

Additional considerations

  • When you shrink a partition, unmovable files (for example, the page file or the shadow copy storage area) are not automatically relocated and you cannot decrease the allocated space beyond the point where the unmovable files are located. If you need to shrink the partition further, move the page file to another disk, delete the stored shadow copies, shrink the volume, and then move the page file back to the disk.

  • If the number of bad clusters detected by dynamic bad-cluster remapping is too great, you cannot shrink the partition. If this occurs, you should consider moving the data and replacing the disk.

    Do not use a block-level copy to transfer the data. This will also copy the bad sector table and the new disk will treat the same sectors as bad even though they are normal.

  • You can shrink simple and spanned dynamic disks, but not others.

Additional references

  • Extend a Simple or Spanned Volume
  • Manage Spanned Volumes
  • Extend a Simple or Spanned Volume
  • Create a Striped Volume