Why Can't I Shrink My C Drive With All of the Space Free?

Windows 11 C drive shows 100GB free space, cannot shrink C drive 100GB free space or even 90GB free space?

Windows 11 C drive shows 60GB free space, can't shrink C drive 30GB free space?

The Problem: C drive shows a lot free space, however can't shrink drive with all free space? Struggling to shrink your C drive in Windows 11 or 10? You're not alone. Even when it seems like space is free, Windows might not allow shrinking due to hidden system files or other restrictions. Let’s explore why—and how to fix it.

Why Windows Won't Let You Shrink the C Drive

Common Causes: Here are typical reasons why Windows blocks shrinking your C drive:

• System Files in the Way: Critical files like pagefile.sys, hiberfil.sys, or restore points are immovable.
• Fragmented Free Space: Free space might be too fragmented for Windows to shrink the partition effectively.
• File System Issues: Only NTFS drives can be shrunk. Non-NTFS file systems like FAT32 or exFAT are not supported. Check your drive format in File Explorer → right-click → Properties.

Quick Fix: Use a free tool like Partition Resizer to shrink the C drive even when Windows can’t—ideal for bypassing unmovable files or limitations.

Watch: How to Shrink C and Extend D or E

Also read: How to shrink C and extend another drive

Step-by-Step Troubleshooting Guide

Before trying any of the following, we highly recommend using the free tool Partition Resizer to shrink the C drive without losing data, as it offers an easy-to-use interface and removes many of Windows' limitations.

1. Temporarily Disable System Protections

Windows may prevent shrinking the C drive due to unmovable system files. Disabling these features temporarily allows you to shrink the volume more freely. Just make sure to turn them back on afterward.

• Disable the Page File (Virtual Memory):
  1. Press Win + R → type sysdm.cpl and hit Enter.
  2. Go to the Advanced tab → under Performance, click Settings.
  3. Switch to the Advanced tab → click Change under Virtual Memory.
  4. Uncheck "Automatically manage paging file size for all drives".
  5. Select drive C:, choose No paging file → click Set, then OK.
  6. Restart your computer to apply the changes.
• Turn Off Hibernation:

  Open an elevated Command Prompt (right-click and choose “Run as administrator”) and enter:

  powercfg /hibernate off

  This disables the hiberfil.sys file, which is often locked and takes up gigabytes of space.

• Disable System Restore:

  In sysdm.cpl, switch to the System Protection tab. Select the C: drive and click Configure. Choose Disable system protection and apply the changes.

2. Free Up Space Like a Pro

Before attempting to shrink your C drive, it's essential to clean up unnecessary files that may be using valuable disk space or blocking the shrinking process.

• Use Disk Cleanup:

  Press Win + S, type Disk Cleanup, and select the C: drive. Once it scans, click "Clean up system files" to remove leftover update files, error reports, temporary files, and more. This step alone can free several gigabytes.

• Manually Delete Temp Files:

  Open File Explorer and go to C:\Windows\Temp. Select all files and delete them. If prompted for admin access, confirm the action. This folder often stores leftover installation files and caches that can be safely removed.

3. Optimize Your Drive

Even with space available, fragmentation or file system errors can prevent shrinking. These tools help optimize your drive for partition changes:

• Defragment Your HDD:

  (Only for hard drives, not SSDs) Press Win + S and search for “Defragment and Optimize Drives”. Select drive C: and click Optimize to defragment files and consolidate free space.

• Run CHKDSK (Check Disk):

  Open Command Prompt as Administrator and type:

  chkdsk C: /f /r

  Confirm the scan to run on the next restart. This checks for file system errors and relocates bad sectors.

4. Perform the Shrink

Once the drive is optimized and system files are out of the way, you're ready to shrink the C partition.

1. Press Win + X → choose Disk Management.
2. Right-click on the C: drive and select Shrink Volume.
3. Enter the amount of space you want to shrink (in MB) and click Shrink.

If the shrinkable space still appears smaller than expected, consider using a third-party tool like IM-Magic Partition Resizer for more flexibility.

5. Restore System Functions

After you've resized your partition successfully, it’s important to re-enable the features you turned off earlier:

• Page File: Repeat the steps from above and set the option to System managed size. Don’t forget to recheck the box for "Automatically manage paging file size for all drives."
• Hibernation: Re-enable it by running powercfg /hibernate on in an Admin Command Prompt.
• System Restore: Go back to the System Protection settings, select C:, and turn protection back on. Allocate around 5–10% of space for restore points.

Final Word: Advanced Options

If none of the above methods work, or if you’re looking for an easier alternative, try one of these advanced tools:

• IM-Magic Partition Resizer – A user-friendly and free utility that allows resizing partitions even when system files block Windows’ built-in tools.
• GParted Live USB – A powerful open-source partition editor. Requires creating a bootable USB, but works outside of Windows and bypasses file locking entirely. Recommended for advanced users.

Important: Always create a backup before resizing or modifying partitions. While these steps are safe if followed correctly, having a recovery plan is critical for your data's security.

Pro Tip: Partition Resizer, the free disk management tool offers clone disk as well as clone partition for free that you may use this free tool for data backup. Data safety first.