How to extend system/OS partition in Windows 11 computer

by John, Published on: August 16, 2021

The same with previous versions, system partition C is running out of space in Windows 11 computer. What will do in that case, reinstall operating system and programs? No, nobody likes to do that. Instead, many people want to extend the system drive without losing data. Windows has native Disk Management tool to help extend partition, but because of some restrictions, it is not the best tool. In this article, I'll introduce how to extend system partition in Windows 11 laptop/desktop/tablet with Disk Management and free partition software. There are several ways to increase system partition size, select the corresponding method according to your own disk partition configuration.

1. Extend system partition in Windows 11 without software

From Windows 7, there's new "Extend Volume" function added in Disk Management. It has the ability to extend NTFS partition without losing data. However, it only works when there's contiguous Unallocated space on the right side. Disk Management cannot make such required Unallocated space by shrinking partition. Therefore, you must delete the adjacent partition after the system drive. Otherwise, Extend Volume option is always disabled.

How to extend system partition in Windows 11 with Disk Management tool:

  1. Right click Windows logo on the bottom taskbar and click Disk Management in the list.
  2. Right click the adjacent partition on the right (D: in most of computers) and select "Delete Volume".
  3. Right click system partition C and select "Extend Volume" option.
  4. Simply click Next button till Finish in pop-up Extend Volume Wizard.

Caution: do not delete D drive if you installed programs in it, remember to transfer files before deleting.

If you don't want to delete any partition and keep everything the same with before, you'd better run third party partition software.

2. Better way to extend OS drive with free partition software

Third party software can make Unallocated space on the left when shrinking D and other partitions, so C drive can be extended easily with the adjacent Unallocated space. In this way, operating system, programs and associated settings, as well as anything else keep the same with before.

There's potential system damage and data loss risk while shrinking partition. Therefore, back up in advance and run safe partitioning software. Better than other tools, NIUBI Partition Editor has powerful Virtual Mode, Cancel-at-well and 1-Second Rollback technologies to protect system and data.

NIUBI Partition Editor has free edition for Windows 11/10/8/7/Vista/XP home computer users. To shrink and extend partition, you just need to click, drag and drop.

Download the free edition, you'll see all storage devices with partition layout and other detailed information on the main window.

NIUBI Partition Editor

How to extend OS partition C: in Windows 11 with NIUBI Partition Editor:

  1. Right click the adjacent partition D (or E: in some computer) and select "Resize/Move Volume" option, drag left border towards right in the pop-up window. If you want to get integer Unallocated space, enter an amount in the box of "Unallocated space before".
  2. Right click system C: drive and select "Resize/Move Volume" again, drag right border towards right to merge this Unallocated space.
  3. Click OK and back to the main window, click Apply on top left to take effect.

If you want to extend C drive by shrinking a nonadjacent partition (such as E: drive in my computer), there's an additional step to move Unallocated space before adding to C drive. Follow the steps in the video to extend system partition C in Windows 11 computer:

Windows 11

In few computers, there's single C drive or not enough free space on the same disk. In that case, you can extend system volume with a larger disk. Remember, no software can extend a partition by adding space from another separate disk.

3. How to increase system partition size with another disk

The strategy is copying the system disk to a larger one and extend system partition (and other volumes) with additional disk space. But before doing this, make sure you can replace hard disk by yourself. Otherwise, you'd better ask help from professional.

Steps to extend system volume in Windows 11 by cloning to a larger disk:

  1. Connect the larger disk to this computer.
  2. Right click the front of system disk (Disk 0 in most cases) and select "Clone Disk".
  3. Select the larger disk in next window. Note: all partitions in this disk will be deleted.
  4. Edit partition size and location, start from the last one.
  5. Click Apply to take effect, remember to click the option to turn off computer.
  6. Replace original system disk or change BIOS to boot from the larger disk.

Watch the video how to operate:

Windows 11

Besides shrinking, extending partition and copy disk partition in Windows 11/10/8/7/Vista/XP computer, NIUBI Partition Editor helps you do many other disk partition management operations.

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