C drive out of space

Solution of C drive full in Windows Server 2012

The same with other Windows Operating System, Server 2012 C drive is also getting full in some day, no matter you use physical hard disk or RAID arrays. When the system C: drive is full, it’ll displayed as red in Windows Explorer, for example:

C drive is full

In this situation, you may try to free up disk space with Server 2012 Disk Cleanup or other tools, but generally speaking you cannot get large amount of free space, so C drive becomes full again very quickly. In this article, I’ll introduce another better solution to fix C: drive full in Windows Server 2012 (R2).

In most of the Windows PC and Server, there is another volume such as D behind C drive in the same hard disk. You can transfer free space of D into C drive with partition software such as NIUBI Partition Editor. By this method, C drive will have plenty of free space again. No other operations are needed, Operating System and everything else keeps the same, so you can solve this problem fast and easily.

Any difference with RAID array?

It is very common to use hardware RAID array, especially RAID 1 for server Operating System. About resizing partitions, there is no difference if you use single hard disk, RAID 1 or RAID 5. It also doesn’t matter which RAID controller or how you build this RAID array.

Only one point: open Server Disk Management, if drive D or other volumes are in the same disk of C drive, you can increase C drive free space easily. In addition, the steps to resize RAID volumes are absolutely the same with resizing physical disk drives.

How to fix C drive full on Server 2012?

Download NIUBI Partition Editor, you’ll see all partitions and corresponding detailed info of each partition on the top. On the bottom you’ll see all disks with partition layout. As you see, drive C, D and E are in Disk 0. On the left side or right click a partition, you’ll see available operations (unavailable operations to this partition are hided).

There is 57.35GB free space in drive D, so we can transfer part of the free space to C drive, steps:

1. Right click drive D and select Resize/Move Volume.

Resize Volume

In the pop-up window, drag the left border rightwards to shrink it.

Shrink D drive

Click OK and this program will back to the main window, 21.46GB Unallocated space is generated behind C: drive.

Unallocated space created2. Right click C drive and select Resize/Move Volume again, in the pop-up window drag the right border rightwards.

Increase C drive

Unallocated space is added into C drive, click Apply on top left to execute, done.

C drive extended


  1. The operations you do won’t be proceed immediately, instead, they’ll be listed as pending on bottom left. You can undo or redo these operations, physical disk drives won’t be modified until clicking Apply to confirm.
  2. All pending operations with  in front can be done in Windows without rebooting server.

In Summary

When system C drive is full in Windows Server 2012, run NIUBI Partition Editor to extend C drive by taking free space from other volumes in the same disk. You’ll have plenty of free space in C drive again without doing anything else. Windows Server 2012 C drive full issue can be fixed fast and easily.

Besides resizing disk drives, this partition software can do many other disk and partition operations. Its enterprise edition can be registered on unlimited Windows PCs and Servers within your organization.