Cannot shrink system partition in Windows 10

Updated on: November 16, 2019

This article explains why unable to shrink system partition in Windows 10 Disk Management and the solution if cannot shrink system volume.

Some people like to use Windows built-in utilities, thinking they have the best compatibility. It is correct in some respect but these tools are usually not powerful. To repartition hard drive in Windows 10, there is Disk Management, which has Shrink and Extend Volume functions.

Shrink Volume can shrink system drive and data partitions easily and without rebooting computer. However, in some special situations, it cannot shrink or can shrink only little space. In that case, you need to run 3rd party partitioning software.

Reasons why can't shrink system partition

Reason 1: not enough free space

In the shrinking volume, Disk Management calculate the available free space give you maximum amount by default, if you manually entered a larger amount, or much free space is used by other files before clicking Shrink, you'll receive the error that "there is not enough space available".

Not enough space

Reason 2: File system or other error

If there are file system error or other system issue, you can't shrink system partition in Windows 10 Disk Management even for 1MB.

Reason 3: FAT32 partitions can't be shrank.

Only NTFS partition is supported, FAT32 and any other types of partitions cannot be shrank. However, few people will encounter this issue, because nearly all system partitions are formatted as NTFS.

Can't shrink system volume

Reason 4: There are unmovable files

If there are some unmovable files are located in system partition such as Paging file and hibernation, Disk Management can only shrink little space.

Unmovable files

What to do if unable to shrink system volume

When you are unable to shrink system drive in Windows 10 Disk Management, check if it is the same with one of the reasons listed above, then find the corresponding solutions below:

Solution 1: Simply repeat shrinking with new default space or enter an smaller amount manually.

Solution 2: Fix file system error.

  1. Type cmd in search box on bottom left corner, right click Command Prompt and select Run as administrator.
  2. In the command window, type chkdsk C: /f /r and press Enter. It will ask you whether schedule check when system restart, type Y and press Enter.
  3. Reboot your computer.

Solution 3: Run professional partition software when shrinking a FAT32 partition or the volume with Unmovable files.

Shrink volume with free partition editor

Download NIUBI Partition Editor, right click system partition C and select "Resize/Move Volume".

if you drag left border towards right in the pop-up window:

Resize partition C

Unallocated space is generated on the left side of C drive.

Shrink C

If you drag right border towards left in the pop-up window:

Resize partition C

Unallocated space is generated on the right side of C drive.

Shrink C

Follow the steps if you want to shrink C drive to expand D.

In most cases, you can shrink system partition in Windows 10 via native Disk Management without issue. If you encountered any error, find out the reason and corresponding solution.

NIUBI Partition Editor has free edition for home users, besides shrinking and extending partitions, it helps you move, merge, convert, defrag, copy, wipe, scan, hide partition, etc.