Shrink System C Drive in Windows Server 2019

by Andy, Updated on: March 26, 2020

This article introduces how to shrink C drive in Windows Server 2019 without losing data, shrink system partition to increase D or expand system reserved partition.

The most common issue in Windows Server is low disk space, especially to system C drive, so you need to expand it to larger size. But in some servers, administrators need to shrink C drive, for example: if you forget to create more partitions while installing Operating System, , you'll get a large C drive that occupies all disk space except some small partitions. In some servers, system reserved partition or data drive D is getting full, you can decrease C drive to expand these partitions. In this article I'll show you how to shrink system C drive with Windows Server 2019 native Disk Management and third party partition editor software.

Shrink C drive in Windows Server 2019 without software

Windows Server 2019 Disk Management has built-in Shrink Volume function to help decrease partition size without losing data (in most cases). Better than 3rd-party software, Disk Management can shrink system partition C on the fly (without rebooting). But, it can only shrink a partition towards left and make Unallocated space on the right. In addition, it cannot shrink C drive under some particular environment.

Steps to shrink C drive partition in Windows Server 2019 Disk Management:

  1. Press Windows and X on the keyboard and click Disk Management in the list.
  2. Right click C drive and select Shrink Volume.
  3. Enter an amount of space and click Shrink, if you do not enter a value manually, maximum available space will be used.
    Shrink C:

In general, C drive will be shrunk in a short time.

Cannot shrink C drive in partition Server 2019 Disk Management

After the last step, my C drive is shrank to 39.4GB and there is 28.95GB free space in it. But when I shrink C drive again, the maximum available space is only 19072MB (18.63GB).

Can't shrink C drive

Many people feedback similar issue, some people can only shrink little space, some people cannot shrink C drive with even 1MB. Why there's such issue? If you noticed the tip in this shrinking window, you'll understand the reason. As it shows, you cannot shrink a volume beyond the point where any unmovable files are located.

For example, if there are unmovable files located in block 3, you cannot shrink C drive to block 2 or 1 even if there's free space there.

Unmovable files

Shrink system C drive with partition editor software

Comparing with Server 2019 Disk Management tool, NIUBI Partition Editor has more advantages while shrinking partition such as:

The same with other software, it requires server rebooting to shrink system C: drive, but better than other tools, NIUBI Partition Editor is much safer and faster because of its advanced technologies such as:

Download NIUBI Partition Editor, right click a NTFS or FAT32 partition and select "Resize/Move Volume". In the pop-up window, there are 2 options.

Option 1: If you drag left border towards right or enter an amount in the box of Unallocated space before, then Unallocated space is made on the left.

Shrink towards right

Option 2: If you drag right border towards left or enter an amount in the box of Unallocated space after, then Unallocated space is made on the right.

Shrink towards left

Video guide to shrink C: drive in Windows Server 2019 and expand D or system reserved partition:

Video Server 2019

Besides shrinking and extending partitions, NIUBI Partition Editor helps do many other disk and partition management operations.