Cannot Shrink Volume — How to Fix in Windows Disk Management
Windows Disk Management's Shrink Volume tool calculates how far back it can shrink a partition based on the last unmovable file on the disk. When it reports a maximum shrink size much smaller than expected — or shows 0 MB available — unmovable system files are blocking the operation. This guide covers every method to remove those blocks and recover the space.
Quick Answer
Why can't I shrink my C: drive further?
Windows Disk Management cannot move certain system files — specifically the hibernation file (hiberfil.sys), the page file (pagefile.sys), System Restore shadow copies (VSS snapshots), and some Windows metadata files. These files sit at the end of the partition, and Windows won't shrink past them. Disabling hibernation and the page file temporarily removes these blocks and often allows a much larger shrink.
Why the Shrink Is Blocked — The Technical Explanation
When you shrink a partition, Windows moves files from the end of the partition to earlier positions — except for files marked as "non-movable" or "non-relocatable." These include:
| File / Feature | Why It Blocks Shrink | How to Remove |
|---|---|---|
| hiberfil.sys (Hibernation) | Fixed at the end of the volume by the OS. Size = total RAM. | Disable hibernation via powercfg |
| pagefile.sys (Page File) | Virtual memory file, locked by Windows while running. | Temporarily disable or move to another drive |
| VSS Snapshots (System Restore) | Shadow copy storage is placed after all other data. | Delete shadow copies / disable System Restore temporarily |
| $UsnJrnl (Change Journal) | NTFS metadata journal, fixed position. | Delete journal with fsutil (advanced) |
| Windows hibernation metadata | Kernel power management files. | Covered by disabling hibernation |
Back up before shrinking. While shrinking itself rarely causes data loss, you are modifying the partition table. Create a full backup or at minimum note down your current partition sizes before proceeding.
Open Command Prompt as Administrator
Press the Windows key, type "cmd", right-click Command Prompt in the results, and select "Run as administrator".
Disable hibernation
Type the following command and press Enter: powercfg /hibernate off — This deletes hiberfil.sys immediately. The file can be 8–64 GB on systems with large amounts of RAM.
Retry Disk Management Shrink Volume
Reopen Disk Management (or press Action > Rescan Disks). Right-click C: and select Shrink Volume. The maximum shrink value should be significantly larger now.
Re-enable hibernation after shrinking (optional)
After the shrink is complete, re-enable hibernation if needed: powercfg /hibernate on — Only skip this if you never use the hibernate power state.
Open System Properties — Advanced
Right-click This PC > Properties > Advanced system settings > Performance Settings > Advanced tab > click "Change" under Virtual Memory.
Disable the page file on C:
Select C: in the list. Choose "No paging file" and click Set. Accept the warning dialog. Click OK on all windows.
Restart Windows
The page file change requires a restart to take effect. After restarting, pagefile.sys will no longer be present on C:.
Shrink C: in Disk Management
Now retry the Shrink Volume operation. With both hiberfil.sys and pagefile.sys removed, you should be able to shrink significantly further.
Re-enable the page file after shrinking
Return to Virtual Memory settings and restore the page file on C: (or select "System managed size"). Restart again. Running without a page file for an extended period can cause stability issues on systems with limited RAM.
Open System Properties — System Protection
Right-click This PC > Properties > System protection. Find your C: drive in the list and click Configure.
Delete all restore points
Click "Delete" to remove all existing shadow copies and restore points for C:. This frees the VSS storage blocks at the end of the volume.
Temporarily disable System Protection
Select "Disable system protection" and click Apply. This prevents new shadow copies from being created during the shrink.
Shrink the volume
Now retry Shrink Volume in Disk Management. After completing the shrink, re-enable System Protection if you use System Restore as a recovery method.
Method 4 — Use a Third-Party Tool (Best for Large Shrinks)
Third-party partition managers like AOMEI Partition Assistant and MiniTool Partition Wizard can move unmovable files by operating in a pre-boot environment — before Windows loads the system that locks those files. This allows you to shrink C: to the actual minimum possible size rather than the conservative limit Windows imposes.
Both AOMEI Partition Assistant Standard (free) and MiniTool Partition Wizard Free can perform pre-boot partition operations. When you schedule a resize of C:, the tool adds the operation to a boot-time queue and executes it before Windows starts on the next restart — bypassing all file lock limitations.
Checking Shrink Progress with Event Viewer
After a shrink attempt, Windows records which files blocked the operation in the System event log. You can view this to understand exactly what is blocking you before trying fixes blindly.
# In Event Viewer, navigate to:
Windows Logs > Application
Source: defrag
# Look for Event ID 259 — it lists the files that cannot be moved