Extend Unallocated to C

Extend C drive in Windows 2012 Server without starting over

It cannot be better if you can extend system C: drive when it is running low, nobody likes to start from scratch. Some people feedback the bad experience: when they contact support from the server manufacturer such as DELL and HP about what to do when C drive is out of free space, they got reply that they have to back up everything, delete and recreate the volumes, finally restore everything.

If you do like that, your whole happy weekend will be wasted, however, it is easy to understand why they give such troublesome solution. Partition software may cause damage to the server storage, so they won’t recommend any software officially. Actually, there is data loss and/or system damage risk indeed if you use some unreliable partition tool. In this article I’ll introduce a safe partition software and how to extend C: drive on Windows Server 2012 (R2) without losing data.

Extend C drive

Partition software for Windows Server

What is most important to a server? It should be data and keeping online. As I said above, there is system damage and data loss risk if resizing volume with unreliable partition program. If damage happen, it costs a long time to restore and verify data. During this period, the server is offline. So the first thing before extending C drive is selecting a right partition software for server.

Search the safest partition software by Google and you’ll see NIUBI Partition Editor. The GUI and functionalities are similar with other tools, but better than all other tools, NIUBI PE is integrated unique and innovative rollback technology, which can ensure 100% system and data safe while resizing volume.

How it works?

After starting this program, NIUBI Partition Editor will take a snapshot of the disk drives. It has internal monitoring strategy during the process of resizing and extending C drive. If any internal error is detected that cannot be handled, or any external hardware issue such as power failure occur, it automatically cancel the operations and roll back to original status in one second. Yes, ONE second.

You cannot see the snapshot or use this program as daily backup plan, rollback only works when something goes wrong while repartitioning disk drives. If it happens, the server could back online without damage in a flash.

NIUBI Partition Editor

As the best partition software, besides protecting data and fast recovering, another main benefit of NIUBI is fast resizing. Thanks to the special file-moving algorithm, it is 30% to 300% faster than other tools. Saving much time if there are large amount of files in the partitions.

How to extend C drive on Server 2012

To resize partitions and extend C drive in Windows Server 2012, you just need to click and drag on the program. If you use hardware RAID such as RAID 0, 1, 5, 10 or virtual machines such as VMware and Hyper-V, the steps are the same with resizing physical disk drives.

Steps to extend system C: drive in Windows 2012 Server:

Step 1: Download NIUBI Partition Editor Server, right click the adjacent drive D and select Resize/Move Volume

Resize/Move Volume

In the pop-up window, drag left border rightwards to take free space out from D.

Resize volume D

Step 2: Unallocated space is generated behind C: drive. (if you drag right border leftwards, Unallocated space will be generated behind D.) Right click C: drive and select Resize/Move Volume again.

Resize volume C

In the pop-up window, drag right border rightwards to combine the Unallocated space.

Extend C drive

Step 3: C drive is extended to 50GB. Click Apply button on top left to execute, done.C drive resized


  1. To avoid mistake, these operations won’t be done immediately, you should click Apply to confirm.
  2. You can undo and redo the pending operations before clicking Apply.
  3. The pending operations with  can be done in Windows without rebooting server.

Only 3 steps by clicking and dragging, you can extend system C: drive on Server 2012 without data loss.

Video guide

NIUBI Partition Editor is compatible with Windows Server 2016, 2012, 2008, 2003 (R2) and Small Business Server 2012 to 2003. Windows 10, 8, 7, Vista and XP are supported, too.

NPE Enterprise Edition can be installed to unlimited PCs and servers in your company, regardless of locations.

If you provide IT service to other companies or individuals, NPE Technical edition can be used to provide profitable service to unlimited clients.

Download to try