Extend system partition in Windows Server 2016

Updated on: November 16, 2019

This article introduces how to extend system partition in Windows Server 2016 without losing data. 3 ways to extend OS partition for Windows 2016 server.

To many server administrators, it is not an easy task to extend system partition in Windows Server 2016, because system partition is where Operating System installed in and booting from, any error could cause system boot failure.

If you back up everything, recreate partitions and restore, it may cost a whole day, server is offline during this operation. This article introduces how to extend OS partition in Windows 2016 server with native Disk Management tool and 3rd-party safe partition software.

Extend OS partition in Server 2016 Disk Management

Some people like to use Windows native utilities, thinking it has best compatibility. There is indeed a built-in Disk Management tool, which is able to shrink and extend partition. The benefit is that it can resize partition without rebooting server, but it is not 100% safe, because it damaged my partitions several times.

Disk Management can only help you extend NTFS partition by deleting the right contiguous volume, in addition, the two partitions must be the same Primary or Logical.

Cannot extend volume

As you see in the screenshot, Extend Volume is disabled for C and E drive after shrinking D in Disk Management. This is because:

After shrinking D, the 20GB Unallocated space is non-adjacent to system C drive and is on the left of drive E, so Extend Volume doesn't work.

If your disk partition configuration meet the requirements:

  • There's another partition (such as E:) that has enough free space to store all files in drive D.
  • There are no programs or Windows services installed in drive D.
  • Drive D is a Primary partition.

Follow the steps to extend OS partition C in Server 2016 Disk Management:

  1. Transfer all files in drive D to E.
  2. Right click D drive in Disk Management and select Delete Volume.
  3. Right click drive C and select Extend Volume.
  4. Click Next till Finish in the pop-up Extend Volume Wizard windows.

If drive D is Logical or you cannot delete this partition, you cannot extend system partition with Windows Server 2016 Disk Management.

Extend system volume with disk partition editor

When resizing partitions, all parameters of associated disk, partitions and files must be modified correctly, all files in the partition that you want to shrink must be moved to new locations. When extending system partition, the boot related files must be updated, too. If any error occur during this process, unreliable software could cause system boot failure, partition corruption or data loss. In that case, it costs a long time to restore everything.

Better than other tools, NIUBI Partition Editor has powerful technologies to protect system and data, for example:

It is also 30% to 300% faster because of the advanced file-moving algorithm.

Download NIUBI Partition Editor Server, you'll see all disks with graphical partition structure on the right side. Available operations to the selected disk or partition are listed on the left and by right clicking.

NIUBI Partition Editor

Firstly, check if there is free unused space in any data volumes on the same disk. If yes, follow the steps below.

How to extend system partition in Windows Server 2016 by shrinking D:

  1. Right click drive D and select "Resize/Move Volume", drag the left border towards right in the pop-up window, then drive D will be shrunk and some Unallocated space will be made on the left of it.
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine this Unallocated space.
  3. Click Apply on top left to execute.

If there's not enough free space in the contiguous partition D, you can shrink any nonadjacent volume on the same disk, but before adding Unallocated space to system C drive, there's an additional step to move partition D.

Video guide to extend system partition C:

Video guide

In some servers, there is single C drive in a disk. Some servers have C and D on the same disk, but there's not enough free space in drive D. In that case, you can copy disk to a larger one and extend system partition with additional disk space.

Follow the steps in the video to extend OS partition in Windows Server 2016 by copying disk:

Video guide

If you use any types of hardware RAID arrays such as RAID 0/1/5/10, do NOT break array or do any operations to raid controller, simply follow the steps above. There is no difference to extend system volume on RAID array or physical hard disk.

Extend system partition in VMware/Hyper-V

If you run Server 2016 as virtual machine in Hyper-V or VMware, the steps are the same to extend system partition if there's available free space on the same virtual disk.

Better than physical disks and RAID arrays, if virtual disks become full, you can expand them directly.

After expanding virtual disk, additional space will be shown as Unallocated on the end of original disk, then you can merge this Unallocated space to system partition and other volumes.

In Summary

Windows Disk Management cannot extend system partition by shrinking any data volumes. You can achieve by deleting the adjacent partition D in some cases, but it is not a good idea. The best way to extend system partition in Windows Server 2016 is running reliable partition software. Because of the powerful data protection ability, fast file-moving algorithm and other benefits, NIUBI Partition Editor is the best choice to accomplish this task. Find out your own server disk partition structure and follow corresponding method above.