Windows Server 2012 Add Space to C Drive

Updated on: November 16, 2019

This article introduces how to add space to system C drive on Windows Server 2012 R2, 4 ways to add free or Unallocated space to C drive without data loss.

When system C drive runs out of space, nobody likes to start over, of course it can't be better if you can add more free space to C drive without reformatting and restoring. However, there's potential data loss risk while resizing disk partition, so you'd better back up first and run reliable partition tool. This article gives detailed steps to add space to C drive in Windows Server 2012 with native Disk Management and 3rd-party safe software.

Add disk space with Server 2012 Disk Management

Windows Server 2012 Disk Management inherited Shrink and Extend Volume functions to change size of allocated partition without losing data (not 100%), so many people try to add free space to C drive from D or other partition. In fact, you can't add disk space to C drive in Disk Management by shrinking another one.

Extend volume disabled

As you see in my server, I got 18.96GB Unallocated space after shrinking drive D, but Extend Volume greyed out for both C: and E: drive.

This is because:

C: drive is nonadjacent and E: is on the right of the Unallocated space, so Extend Volume doesn't work for them.

The only way to expand C drive with Disk Management is by deleting the adjacent partition (D:).

How to add disk space to C drive in Windows Server 2012 Disk Management:

  1. Back up or transfer all files in the right contiguous partition (D:).
  2. Press Windows logo and X together on the keyboard, click Disk Management from the list.
  3. Right click drive D: and select Delete Volume. (Don't do this if you installed programs or any Windows services in it.)
  4. Right click system C: drive and select Extend Volume.
  5. Simply click Next till Finish in the pop-up windows.

If the right adjacent partition is Logical, you still cannot extend C drive. If you cannot or don't want to delete partition, third party software is needed.

Add space to C drive from contiguous volume

There are many server partition software in the market and the GUI are all similar, however, some unreliable software could cause system damage and data loss. If it happens, you have to start from scratch or waste a long time to restore everything.

As the safest tool, NIUBI Partition Editor provides 3 innovative technologies to protect your system an data.

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

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

NIUBI Partition Editor

Before expanding C drive, find out whether there's free unused space in any other partitions on the same disk, and then decide which partition to get space from. The way to add space to C drive from contiguous, non-adjacent partition or other disk is different.

Steps to add space to C drive from D on Windows Server 2012 (R2):

  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 left border towards left to combine this Unallocated space.
    Extend C
  3. Click Apply on top left to execute, done. (All operations before this step only work in virtual mode.)C drive extended

Add non-adjacent Unallocated space to C drive

If there is not enough free space in the adjacent drive D, you can shrink E or other non-adjacent partition. In this situation, there's an additional step to move partition D.

  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 middle position towards right in the pop-up window. Then Unallocated space will be moved from right of D to the left.
    Move partition D
  3. Right click C: drive and follow Step 3 above to add Unallocated space to C drive.

Watch the video how to add space to system C: drive in Windows Server 2012 (R2):

Video guide

If there's no available free space in other data volumes on the same disk, no software can add space to C drive from other separated disk. In that case, follow the steps to copy disk to a larger one and expand partition(s) with additional disk space.

Add space to C drive in VMware/Hyper-V

If you run Windows Server 2012 as guest virtual machine in VMware or Hyper-V, firstly, check if you can shrink any data volume to get Unallocated space on the same virtual disk. If yes, there's no difference to add Unallocated space to C drive.

If there's no available free space, you can increase disk size without copying to other one, follow the guide below:

After expanding disk, additional disk space will be shown as Unallocated on the end of original virtual disk. Follow the method in the video and combine Unallocated space to C drive or other partition(s).

In Summary

Windows Disk Management cannot extend C drive by shrinking another one. To add space to C drive on Windows 2012 server, you'd better back up and use safe partition software. Because of the powerful data protection technologies, NIUBI Partition Editor helps you complete this task fast and safely. It also helps you do many other disk partition operations.