This article explains why unable to shrink volume in Windows 10 Disk Management (32 & 64 bit) and what to do when cannot shrink partition on Windows 10.
Better than third party software, Disk Management can shrink C drive on the fly without rebooting. But, Shrink Volume function has some limitations which cause you cannot shrink volume or can only shrink little space. In this article, I'll show you most common reasons why can't shrink volume via Windows 10 Disk Management and alternative solutions.
Cannot shrink volume towards right
It is very easy to shrink partition via Disk Management, right click this partition and select "Shrink Volume", then enter an amount to shrink.
However, the only option it give you is entering an amount or simply click Shrink to use default maximum space. After that, Disk Management will shrink this partition towards left and generate Unallocated space on the right side for you.
If you just want to shrink a drive to create new volume, it doesn't matter. But if you want to shrink D to expand C, it is impossible, because Extend Volume cannot combine Unallocated space to any non adjacent partitions.
In some situations, Disk Management is unable to shrink partition towards either side.
Why can't shrink volume in Windows 10 Disk Management
FAT32 partitions can't be shrank.
Both Shrink and Extend Volume support NTFS partition only, so FAT32 and any other types of partitions cannot be shrank or extended.
Not enough free space
In the shrink volume, Disk Management give you maximum space by default, if you manually enter an incorrect larger amount, or many files saved to this volume before clicking Shrink, you may receive the error that "there is not enough space available".
File system or other error
If there is file system error or other system issue, Disk Management won't allow shrinking even 1MB.
Unmovable files are located
If there are some unmovable files such as Paging file and hibernation files are located in this partition, Disk Management can only shrink little space.
What to do when unable to shrink partition
If you encountered any error when shrinking partition with Windows 10 Disk Management, you may use 3rd party professional partition software. NIUBI Partition Editor has free edition for home users. It supports shrinking both NTFS and FAT32 partitions. It is able to move the "unmovable" files, so you can shrink a partition to minimum size if you want. To shrink partition in Windows 10 with it, you just need to drag and drop on the disk map.
Download NIUBI Partition Editor, right click drive D (or other one) and select "Resize/Move Volume".
If you drag left border towards right in the pop-up window,
If you drag right border towards left in the pop-up window,
Follow the steps if you want to extend disk partition on Windows 10.