How to extend system partition in Windows Server 2012

by James, Updated on: December 7, 2020

This article introduces how to extend system partition in Windows Server 2012 without losing data. Extend system drive with another volume or disk.

System partition is getting full

Comparing with data partitions, system volume is very likely getting almost full after running the server for a period of time. Even if you installed all programs to anther volume, there are still large amount of junk files generated in system C: drive.

If you contact support from server OEM manufacturers, they'll tell you to back up, delete and recreate all partitions, finally restore everything. If you do like that, your whole weekend may be wasted. With right tool you can extend system partition C in Windows Server 2012 and R2 in a short time.

However, you should always pay attention to any operations to a server, before resizing and extending system partition in Windows 2012 server, there are several points you should know. Find out your own disk partition configuration and follow corresponding method.

Tips before extending system partition in Server 2012 R2

1. Take care of system and data

Unlike the read-only programs such as data recovery software that just read from the hard disk drive. Partition manager software will modify disk partitions, so there is potential system damage and data loss risk, especially when you resizing system partition.

Better than other tools, NIUBI Partition Editor has innovative technologies to protect your system an data.

It is 30% to 300% faster because of the advanced file-moving algorithm. This is very important to a server especially when the operations require reboot.

2. About hardware RAID arrays

Hardware RAID array has advanced abilities, it is realized by raid controller with several disks. But to Operating System, there's no difference if you physical disk or hardware RAID array. When extending system drive in Windows Server 2012 (R2), don't break RAID array or do any operations to the RAID controller, follow the same steps below.

3. Select corresponding solution according to your own partition layout

  1. In most of the servers, there is at least another volume on the same system disk, then you just need to shrink it to get some Unallocated space and add into the C drive.
  2. If you want to shrink any non-adjacent partition to extend system drive, there's an additional step to move Unallocated space behind C drive.
  3. If there is no other partition or not enough free space on entire disk, no partitioning software can help you extend system partition by adding free space from another separate disk. In that case, you can clone system disk to another larger one and extend partition with additional disk space.

How to extend system partition in Windows Server 2012

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

NIUBI Partition Editor

Extend system partition with contiguous volume

In most of servers, there's plenty of free space in the contiguous partition D. In that case, shrink D and make Unallocated space on the left, and then add Unallocated space to C drive.

Steps to extend system partition in Server 2012 R2 with contiguous volume:

  1. Right click D: drive and select "Resize/Move Volume", drag left border towards right in the pop-up window, or enter an amount in the box of Unallocated space before. Then part of free space in drive D will be changed to Unallocated on the left.
    Shrink D
  2. Right click C: drive and select "Resize/Move Volume" again, drag right border towards right to combine this Unallocated space.
    Extend C
  3. Click Apply on the top left to take effect, done. (All operations before this step only work in virtual mode.)C drive extended

Extend system partition with nonadjacent volume

If there's insufficient free space in the contiguous partition D, check if there's another volume (such as E:) with enough free space on the same disk. If yes, shrink it and make Unallocated space on the left, too. Because D drive is in the middle, Unallocated space that shrunk from E is non adjacent to C drive. You should move Unallocated space next to C drive in advance, otherwise, you cannot extend C drive.

Steps to extend system partition in Windows Server 2012 R2 with a nonadjacent volume:

  1. Right click drive E: and follow Steps 1 above to make Unallocated space on the left side.
  2. Right click drive D: and select "Resize/Move Volume", drag the middle towards right in the pop-up window. Then Unallocated space will be moved behind C drive.
  3. Right click C: drive and follow Step 3 above to add Unallocated space to C drive.

Watch the video how to extend system partition with another volume on the same disk:

Video guide

Extend system partition with another disk

In few servers, there's only C drive on the same disk. In some servers, there's other volume on the same disk but there's no available free space to transfer to C drive. As I said above, you cannot add space from another separate disk with any software. In that case, you have 2 options:

1. Copy system disk to a larger one and expand partition with additional disk space:

Video guide

2. Move a volume to another disk, delete it and add its space to system C drive:

Video guide

Extend system volume for Server 2012 VM in VMware/Hyper-V

To save cost or because of other benefits, many companies run Windows Server 2012 as virtual machine. If you want to extend system partition in Server 2012 VM in VMware or Hyper-V, similarly, first check if there's available free space in any other volume on the same virtual disk. If yes, simply install NIUBI Partition Editor in the virtual machine and follow the steps in the video above.

If the entire virtual disk is full and there's no available free space, you can increase virtual disk size easily. After expanding disk, additional disk space will be shown as Unallocated at the end of original virtual disk, then you can combine Unallocated space to the system C drive.

In Summary

To extend system partition in Windows Server 2012/2016/2019/2003/2008, you'd better back up first and run safe partition software. Because of the powerful data protection technologies, NIUBI Partition Editor helps you complete this task fast and safely. Follow the corresponding solution according to your own disk partition configuration. Besides shrinking, moving and extending partition, it helps you do many other disk partition management operations.