Extend C: Drive in Windows Server 2016 Without Losing Data

by Allen, Updated on: July 14, 2022

The same with all previous and latest versions, C drive in Windows Server 2016 is also running out of space. If you use traditional method to back up, recreate partitions and restore everything, it may waste a whole weekend. Some people ask whether it's possible to extend C drive in Windows 2016 server without losing programs and data. The answer is yes. To increase C drive space in Server 2016, you may run native Disk Management or third party software. In this article I'll introduce how to extend C drive in Windows Server 2016 with both kinds of tools.

1. Take care of system and data before resizing partition

Unlike data recovery software that just read information from hard disk, to extend system C: drive in Windows 2016 server, partitioning software will modify the parameters of associated disk, partition and files. In some situations all files in the partition will be moved to new locations.

Therefore, there's potential system damage and data loss risk no matter you use native Disk Management tool or third party software. Some unreliable partition software are called as "data killer" by the people who have experienced such disaster.

For example, if you shrink D to expand C drive, the start position of D and the end position of C drive will be changed. All files in D drive will be moved to new locations. All parameters of these files will be modified, system boot related files must be updated, too. Therefore, any incorrect modification could cause system booting failure and losing data. Besides software internal error, some hardware issue such as power outage cause system and partition damage, too.

2. Which tool to help extend C drive in Windows Server 2016

Windows Server 2016 has "Shrink Volume" and "Extend Volume" functions in native Disk Management tool to help change partition size. However, it can only shrink and extend NTFS partition, FAT32 and any other types of partitions are not supported. Some people think that Windows native tools have best compatibility, but it's not. Disk Management damaged my partitions several times when shrinking partition. Pay more attention if there are both Primary and Logical partitions on a disk.

If you want to extend C drive in Windows Server 2016 without any software, you must delete the contiguous partition D (or E). In additional, this contiguous partition must be Primary. Because "Extend Volume" function in Disk Management only works when there is adjacent Unallocated space behind C drive. If you shrink D or any partition with "Shrink Volume" function in Disk Management, Unallocated space is always nonadjacent to C drive. This is the reason why many people feedback that they cannot extend C drive after shrinking other volume.

To extend C drive partition in Server 2016, third party software are much more powerful but few are safe enough. Better than other tools, NIUBI Partition Editor has innovative technologies to protect your server system and data.

Virtual Mode

It is designed to work in its virtual mode first. The operations you do won't be executed immediately. Instead, they'll be listed as pending on bottom left, you can preview or click Undo to cancel any unwanted operations. Real disk partitions won't be modified until you click Apply button to confirm.


Other software don't allow you canceling the ongoing operations even if you did something wrong, because the cancellation causes part of the parameters failed to be modified, then damage occur. But while running NIUBI you can cancel the ongoing operations at any progress without losing data.

1-Second Rollback

If any software or hardware issue occur while resizing and extending partition, it is able to automatically reverts the server to original status in a flash. If it happens, nothing will be changed, so your server could back online rapidly without damage. This is innovation in Disk Management industry.

With the help of "Hot Clone" technology, it doesn't require server rebooting to clone disk partition with NIUBI Partition Editor. You may clone system disk before resizing partitions or regularly as backup. Whenever the system disk is down, you can swap and boot from the clone disk in several minutes.

In addition, it is 30% - 300% faster because of its advanced file-moving algorithm, it saves much time when you shrinking or moving a partition with large amount of file. These abilities are very helpful and important when resizing server partitions.

3. How to extend C drive in Server 2016 SSD/HDD/RAID

In most of servers, there is another partition such as D on the same disk, so you can shrink it to get Unallocated space and then add into C drive. By doing this, Operating System, programs and associated settings, as well as anything else keeps the same with before. Better than Disk Management, NIUBI Partition Editor can make Unallocated space on the left when shrinking partition, so C drive can be extended easily after shrinking D.

Download NIUBI Partition Editor, 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. In my 2016 server, C drive is 40GB and D is 70GB.

NIUBI Partition Editor

Steps to extend C: drive in Windows Server 2016 without losing data :

  1. Right click D: drive (the adjacent partition) and select "Resize/Move Volume", drag left border towards right in the pop-up window. Then Unallocated space is made on the left.
  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, done.
    C drive extended

If there is not enough free space in the adjacent D drive, you can shrink nonadjacent partitions on the same disk (such as E: in my server). In that case, there's an additional step to move Unallocated space before adding to C drive.

How to extend C drive in Windows 2016 server with NIUBI Partition Editor:

Video guide

  • To move partition D, you need to put mouth pointer in the middle of D drive and drag it towards right in the pop-up window.
  • If you use any types of hardware RAID, do not break array or do any operations to RAID controller, there is no difference to resize/extend RAID partition.
  • If there's no other partition or not enough free space on the same disk, no software can extend C drive in Server 2016 by adding space from another separate disk. In that case, follow the steps in the video to expand C drive by cloning disk to a larger one.

4. Extend Server 2012 C drive in VMware/Hyper-V virtual machine

If you want to extend C drive in VMware/Hyper-V running Windows Server 2016 as virtual machine, simply install NIUBI to the guest virtual server and follow the steps above. If there's no available free space on a virtual disk, you can expand this virtual disk directly without copying to a larger one. Additional space will be shown as Unallocated at the end of original disk, then you can combine this Unallocated space to C drive (and other volumes).

Besides resizing partition and extending C drive in Windows Server 2016/2019/2022 and previous Server 2003/2008/2012, NIUBI Partition Editor helps you do many other disk partition operations.