The Symptom
When using Disk Management to shrink a volume or partition, you may find out that the
size of available shrink space in mb 0, even through the partition to be shrunk has
much unused space. the problem is often met when people trying to resize the system
partition, which is also known as the C: drive.

The Cause
According to the warning note in Disk Management shrink volume window that “you
cannot shrink a volume beyond the point where any unmovable files are located.’below
the Total size after shrink in MB box, there must be some unmovable files (page
files or system files) at the very end of the partition that you were trying to
shrink.
The Solution
To fix this problem, you can remove or disable the unmovable files to increase
available shrink space, but the question is that it is hard to find out which
exactly is the file that is stopping you from shrinking volume. Therefore, you need
to disable as many system files as you can to see if it works. You can first disable
System Protection, Hibernation mode, kernel memory dump, and page files as least
temporarily. Then run Disk Defragement, Disk Cleanup. These move shall increase the
available shrink space in Disk Management. Actually, there is a simpler and safer
way to shrink a volume without worrying about no available shrink space by using
third party freeware AOMEI Partition Assistant, which does not have the problem with
shrink volume with
unmovable files. AOMEI Partition Assistant Standard is a free partition
manager software for Windows 10/8/7 that can help you shrink a volume or partition,
no matter where the unmovable files locate.
To shrink partition with AOMEI Partition Assistant:
1. Download and run this partition software
2. Right-click on the partition which needs shrinking and select “Resize
Partition” in the drop-down menu.

3. It will bring you the Move and Resize Partition screen. What’s amazing about this
freeware is that you can shrink the partition from both sizes by dragging the
slider. You can also enter the amount of space to shrink the volume.

4. Preview the partition layout after the shrink. If it contents you, click Apply to
apply the operation.

In a short while it will complete the shrink process, leaving unallocated space on
the disk. With the unallocated space, you can create a new partition, extend the
adjacent partition, or add the unallocated space to a nonadjacent partition by using
Merge Partitions function, which is
available on paid edition like AOMEI Partition Assistant
Professional and Server edition. Besides, AOMEI Partition Assistant is also
capable of many other useful things, such as Migrate OS to SSD, convert dynamic to basic
disk without data loss, and create bootable media. In conclusion, the
problem of the size of available shrink space in mb 0 will never concern you after
trying AOMEI Partition Assistant.