"Available shrink space too small despite plenty of free space (unmovable files issue)"

Hi there,

I'm trying to shrink my C: drive using Windows Disk Management, but the available shrink space is extremely limited — even though I have more than 390 GB of free space on the disk.

When I run:

defrag C: /A /U /V

It tells me:

You do not need to defragment this volume.

But in the report, I see:

Unmovable files and folders = 8

Total free space = ~395 GB

Largest free space block = ~42 GB

🧱 Background:

I had previously installed Ubuntu via VirtualBox, but I have deleted the VM and VirtualBox completely. Still, I can't shrink the partition more than a few GB.

❓ Questions:

What are these "unmovable files" exactly and how do they limit shrink operations?

Is there any safe method to temporarily disable or move them (like hibernation, pagefile, or restore points)?

Are there any Microsoft-recommended tools or procedures to bypass this limitation?

Could using third-party tools (like AOMEI, Defraggler) be dangerous or does Microsoft have official alternatives?

Any help or guidance would be really appreciated. Thanks in advance!Hi there,

I'm trying to shrink my C: drive using Windows Disk Management, but the available shrink space is extremely limited — even though I have more than 390 GB of free space on the disk.

When I run:

defrag C: /A /U /V

It tells me:

You do not need to defragment this volume.

But in the report, I see:

Unmovable files and folders = 8

Total free space = ~395 GB

Largest free space block = ~42 GB

🧱 Background:

I had previously installed Ubuntu via VirtualBox, but I have deleted the VM and VirtualBox completely.
Still, I can't shrink the partition more than a few GB.

❓ Questions:

What are these "unmovable files" exactly and how do they limit shrink operations?

Is there any safe method to temporarily disable or move them (like hibernation, pagefile, or restore points)?

Are there any Microsoft-recommended tools or procedures to bypass this limitation?

Could using third-party tools (like AOMEI, Defraggler) be dangerous or does Microsoft have official alternatives?

Any help or guidance would be really appreciated. Thanks in advance!