How to safely extend system partition (C) on Windows 11 – without extra tools

Yes, it's possible to extend the system drive. The issue is the partition next to it. Here's the fix for Windows 11 devices.

Windows 11 extend system partition
Windows 11 extend system partition / Image: Mauro Huculak

On Windows 11, it’s possible to extend the partition containing the operating system, apps, and files to use the remaining unallocated space on the hard drive, and in this guide, I’ll explain the proper process to complete this configuration without losing your data.

A typical installation of Windows 11 has three partitions, including the EFI (Extensible Firmware Interface) partition, which is a crucial component of the system’s boot process, the “C:” drive, which contains the operating system, apps, and files, and the Recover Partition, which includes the tools to troubleshoot and resolve system issues.

If the hard drive still has some unallocated space, you won’t be able to extend the primary partition because the remaining space is non-contiguous, as the Recovery Partition is next to it. This usually happens if you create the partitions manually or replace the system hard drive with another one with a larger capacity, and you used a cloning or backup tool to transfer the installation to the new drive.

Regardless of the reason, you can still extend the main setup volume to make the additional space usable. However, you would have to delete the Recovery Partition, extend the “C:” drive, and then recreate the Recovery Partition at the end of the drive to complete this process.

In this guide, I will explain how to correctly increase the size of the system partition on Windows 11 to use the remaining unallocated space when the Recovery Partition is next to it.

Warning: You will be modifying the partitions on your computer, which, if it’s not done correctly, could break the installation. It’s recommended to create a full backup before proceeding.

Extend the ‘C’ system drive next to the Recovery Partition on Windows 11

To extend the “C” drive on Windows 11, follow these steps:

  1. Open Start.

  2. Search for Command Prompt, right-click the top result, and choose the Run as administrator option.

  3. Type the following command to disable the Windows Recovery Environment (WinRE) and press Enter:

    reagentc /disable
    Quick note: This command disables the recovery environment and moves the “Winre.wim” image from the “Recovery Partition” to the “Recovery” folder in the “C” drive.
  4. Type the following command to launch DiskPart and press Enter:

    diskpart
  5. Type the following command to list the system drives and press Enter:

    list disk
  6. Type the following command to select the “C” drive and press Enter:

    select disk 0
  7. Type the following command to list the partitions and press Enter:

    list partition
  8. Type the following command to select the Recovery Partition and press Enter:

    select partition X

    In the command, replace “X” with the number that corresponds to the Recovery Partition on your setup.

  9. Type the following command to delete the recovery partition and press Enter:

    delete partition override

    Disable WinRE and delete Recovery Partition

  10. Open Settings.

  11. Click on Storage.

  12. Click on Advanced storage settings under the “Storage management” section.

  13. Click on Disks & volumes.

    Open Disks & Volumes settings

  14. Select the Windows 11 volume and click the Properties option.

    Open drive properties

  15. Click the Change size button.

    Change C partition size

  16. Confirm the “Max” value in the New (MB) setting to indicate the total size of the partition (C:) where Windows 11 is installed, but leave at least 1024MB (1GB) to recreate the Recovery Partition. For example, if the maximum size of the partition that can be used is 307082, then subtract 1024, and use that as the new number (306058).

    Windows 11 extend C partition size to use unallocated space

  17. Click the OK button.

  18. In Command Prompt, type the following command to create a new partition and press Enter:

    create partition primary

    Recreate Recovery Partition on Windows 11

  19. Type the following command to format the partition and press Enter:

    format fs=ntfs quick
  20. Type the following command to register the new partition as the Recovery Partition in the system and press Enter:

    set id=de94bba4-06d1-4d40-a16a-bfd50179d6ac override
  21. Type the following command to lock and prevent users from modifying this partition and press Enter:

    gpt attributes=0x8000000000000001
  22. Type the following command to close the DiskPart tool and press Enter:

    exit
  23. Type the following command to enable WinRE and press Enter:

    reagentc /enable
    Quick note: This action will also copy the “Winre.wim” from the “Recovery” folder to the “Recovery Partition.”
  24. Type the following command to confirm the Windows Recovery Environment is working correctly, and press Enter:

    reagentc /info

After you complete the steps, the “C:” drive will extend to the remaining space, and the new Recovery Partition will be created next to the partition with the Windows 11 setup.

If the “winre.wim” file is missing or you’re dealing with errors, you can create the Recovery Partition using the “winre.wim” file available inside the “install.wim” file from the Windows 11 ISO file.

About the author

Mauro Huculak is a Windows How-To Expert and founder of (est. 2010). With over 21 years as a technology writer and IT Specialist, Mauro specializes in Windows, software, and cross-platform systems such as Linux, Android, and macOS.

Certifications: Microsoft Certified Solutions Associate (MCSA), Cisco Certified Network Professional (CCNP), VMware Certified Professional (VCP), and CompTIA A+ and Network+.

Mauro is a recognized Microsoft MVP and has also been a long-time contributor to Windows Central.

You can follow him on YouTube, Threads, BlueSky, X (Twitter), LinkedIn and About.me. Email him at [email protected].