How to extend system partition in Windows 10

by Allen, Updated on: February 18, 2021

This article introduces how to extend system partition in Windows 10 (32 & 64 bit) with native Disk Management and free partition editor.

Comparing with data drives, system partition is more likely running out of space. To data volumes, you can easily transfer files to other place, but to system partition, it is much more complicated. To solve this problem fast and easily, you'd better extend the system drive with free space in other volumes.

To many people, it is not an easy task to extend system volume for Windows 10 laptop/desktop. In this article, I'll introduce 4 ways to extend system partition in Windows 10 without losing any data. Select the tool and method according to your own disk partition structure.

1. Difference between System and Boot partition

In many people's opinion, system partition is the drive where Operating System is located, but it's wrong.

  • The System partition is a primary partition that contains the files for booting Windows, files include Ntldr, Boot.ini,, bootmgr, BCD, etc.
  • The Boot partition is the partition where Windows is installed, it contains the operating system folder/directory.

Before Windows 7, System and Boot partition are the same one - "C:" drive. But from Windows 7, new added BitLocker requires an unencrypted partition, so System partition is separated from C drive.

To make things simple, we treat system partition as C drive here.

Note: if you want to extend boot partition in Windows 10, you must use third party software such as NIUBI Partition Editor. As the screenshot shows, the System partition is also EFI. Windows native tool cannot shrink, move or extend EFI partition.

System Boot partition

2. Extend system partition with Windows 10 Disk Management tool

The same with Windows 7, Windows 10 has native Disk Management tool with Shrink and Extend Volume functions, so you can change size of allocated partition without losing data (not 100%).

However, to extend system partition in Windows 10 computer, the native Disk Management tool is not the best choice, because it has the same restrictions with previous versions:

  • Only NTFS partition is supported, another common FAT32 partition can't be shrunk and extended.
  • Shrink Volume function can only shrink a partition towards left and make Unallocated space on the right side.
  • Extend Volume function can only extend a partition when there's contiguous Unallocated space on the right.

As you see in the screenshot, Extend Volume is disabled for both C and E drive after shrinking D. This is because that C drive is nonadjacent and E is on the right side of this Unallocated space.

Extend volume disabled

Therefore, the only way to extend system partition via Windows 10 Disk Management is by deleting D drive, then there will be adjacent Unallocated space behind C drive, so Extend Volume will be enabled. Note: don't do this if you installed programs to D drive.

How to extend system partition in Windows 10 using Disk Management tool:

  1. Transfer all files in the right contiguous partition (D:) to other place.
  2. Press Windows and X on your keyboard and click Disk Management in the list.
  3. Right click the adjacent D drive and select Delete Volume.
  4. Right click system C drive and select Extend Volume.
  5. Simply click Next to complete the pop-up Extend Volume Wizard.

If D is a Logical drive, you still can't extend system partition after deleting it.

3. How to extend system drive with free partition editor (3 ways)

Comparing with Windows 10 native Disk Management, third party software is much more powerful, but it doesn't mean any partitioning software can accomplish this task well.

There is potential system and data damage risk while resizing partitions, because all parameters of associated disk, partition and files must be modified correctly. In addition, system boot related files must be updated, too. Some unreliable software could cause Windows boot failure or data loss.

Better than other tools, NIUBI Partition Editor provides unique technologies to protect system and data:

To Windows 10/8/7/Vista/XP home computer users, there's free edition. It is the same with professional edition except lacking of 1-Second Rollback and bootable media builder.

Download and install this program, you'll see the main window with disk partition structure and other information.

Main window

There are 3 ways to extend system partition for Windows 10 laptop/desktop, select the corresponding method according to your own disk partition structure.

Extend system partition by shrinking the contiguous drive

In most of computers, there is another drive (D:) on the same disk, You can shrink it and make Unallocated space on the left, and then combine to system C drive. In this way, Operating System, programs and associated settings, as well as anything else keep the same with before.

Steps to extend system partition in Windows 10 with NIUBI Partition Editor:

Step 1: Right click D: drive and select "Resize/Move Volume", drag left border towards right in the pop-up window.

Shrink D

Then part of free space will be converted to Unallocated on the left.

Shrink D rightwards

Step 2: Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine Unallocated space.

Extend C drive

Then system C drive is extended from 30GB to 50GB.

Extend volume C

Step 3: Click Apply on top left to execute, done (all operations only work in virtual mode before this step).

Extend system volume by shrinking a nonadjacent drive

In some computers, there is not enough free space in the contiguous partition D. In that case, you can shrink the non-adjacent drive (E:) to get Unallocated space.

Similarly, right click E and follow STEP 1 above to make Unallocated space on the left. Before adding Unallocated space to C drive, there is an additional step to move Unallocated space from right of D to the left side. To do this, right click D: drive and select "Resize/Move Volume", drag the middle towards right in the pop-up window.

Watch the video guide how to extend system partition for Windows 10 computers.

Video guide

Extend system drive with another disk

In some computers, there is no other data volume, or not plenty of free space on the same disk. In that case, no software can add space to C drive from another separate disk. You can clone this disk to a larger one and extend system partition with extra disk space.

Video guide

In Summary

To extend system partition in Windows 10/8/7, the native Disk Management is useless in most cases. You'd better back up and run safe partitioning software. Because of the powerful data protection technology and fast file moving ability, NIUBI Partition Editor is the best choice. Besides shrinking and extending partition, it helps you merge, convert, defrag, wipe, hide, create, delete, format, scan partition, etc.