How to extend system partition in Windows Server 2016

by Jacob, Updated on: July 7, 2020

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 waste a whole weekend, server is offline during this operation. This article introduces fast way to extend OS partition in Windows 2016 server with native Disk Management tool and third party safe partition software.

1. 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.

Windows Disk Management can only help you extend NTFS partition by deleting the contiguous volume on the right, 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: drive, the 20GB Unallocated space is non-adjacent to system C drive and is on the left of E, so Extend Volume greyed out.

If your disk partition configuration meet the requirements:

  1. There's another partition (such as E:) that has enough free space to store all files in D.
  2. There are no programs or Windows services installed in D drive, so you can delete it.
  3. D is a Primary partition.

Follow the steps to extend system 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 C drive and select Extend Volume.
  4. Click Next till Finish in the pop-up Extend Volume Wizard windows.

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

2. Extend system volume with server partition editor

Better than Disk Management, server partitioning software can resize both NTFS and FAT32 partitions, they can make Unallocated space on either side when shrinking partition. They can also merge Unallocated space to either contiguous or nonadjacent partition on the same disk.

However, you'd better back up server and run safe partitioning software, because there's potential risk of system boot failure and data loss.

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 your 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

When extending system drive, firstly, check if there is free unused space in other 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 D: drive and select "Resize/Move Volume", drag left border towards right in the pop-up window, then this partition 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. (All operations before this step work only in virtual mode.)

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 rightwards.

Video guide to extend system partition C:

Video guide

If you use any types of hardware RAID arrays such as RAID 1/5/6/10, 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 volume with another disk

If there's no other partition on the same disk, you can copy system disk to another larger one and extend OS partition with additional disk space.

Follow the steps in the video to extend system drive in Windows Server 2016 by copying disk:

Video guide

If there's other data volume on the same disk, but there's not enough free space, besides copying system disk to a larger one, you can move data partition to another disk, then delete it and add its disk space to C drive.

3. Extend Server 2016 system drive 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 at 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 other volumes. Although you can achieve by deleting the adjacent partition D, obviously it is not a good idea. The best way to extend system partition in Windows 2016 Server 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.