Cannot extend C drive in Windows Server 2012 (R2) Disk Management

From Windows Server 2008, Microsoft provides GUI function in Disk Management to change partition size. It is great improvement to previous editions. With Shrink Volume function, you can decrease an existing partition without reboot. Extend Volume helps you easily increase a partition size. However, many people try to shrink D drive, but found they cannot extend C drive, because Extend Volume is greyed out. In this page, I’ll tell why you cannot extend C drive in Windows Server 2012 (R2) Disk Management, and how to solve this problem in an easy way.

Scenarios of cannot extend C drive

The reason why so many people encountered this problem is because Extend Volume function disabled in most cases. Here I’ll show one by one.

Right-click Windows and click Disk Management.

1. Right click C drive directly, Extend Volume is grayed out.

Cannot extend C

2. Shrink the adjacent drive D and retry.

Shrink drive D

Shrink 10GB space.

Shrink drive D

Right click C drive, Extend Volume is still disabled.

Extend volume disabled

3. Delete drive D and retry.

Delete drive D

You cannot extend C drive, too.

Cannot extend C

4. Delete all volume in the Extended partition and retry.

Delete volume E

Delete the Extended partition.

Delete extended partition

Now, Extend Volume becomes available.

Extend available

As I said above, you cannot extend C drive in Windows Server 2012 in most cases.

Why cannot extend C drive in DM

There are 3 main reasons why you cannot extend C drive with Extend Volume function:

  1. You may use FAT32 file system. From Microsoft explanation, only NTFS and RAW format partition can be extended.
  2. There is no adjacent Unallocated space. Only when the Unallocated space is adjacent and at right side of C drive, you can expand C drive with the Unallocated space.
  3. You did not delete the adjacent Extended Partition. If the adjacent drive D is in the Extended Partition, you cannot extend C drive by simply deleting D. You should delete all volumes in the Extended Partition and then delete the entire Extended Partition.

Extend C drive without deleting

With 3rd-party server partition software, it is much easier to decrease and increase partition size. You can extend C drive without deleting. As long as there is free space in any other drives in the same disk, you can take free space out and add to C drive easily.

Firstly, let’s open Disk Management:

Disk Management

As you see, C drive is 39.66GB and the 10GB Unallocated space (shrank from D) is behind D:.

Download and launch NIUBI Partition Editor, the disk partition layout is the same with Disk Management.

Partition Editor

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

Resize volume

Step 2: In the pop-up window, drag middle position rightwards.

Drag to move

Move partition

Click OK and back to the main window, where the 10GB Unallocated space moved to behind C: drive.

Unallocated moved

Step 3: Right click C drive and select “Resize/Move Volume” again. In the pop-up window, drag the right border rightwards to hold the Unallocated space.

Drag to extend

Extend volume

Step 4: Click OK and back to the main window, where the 10GB Unallocated space added into C drive. Click Apply on top left to execute, done.

Volume extended

Check in Disk Management:

Volume extended

C drive increased to 49.66GB.

The most possible reason why you cannot extend C: drive in Server 2012 is because Extend Volume grayed out, so you cannot extend C drive after shrinking D. In this situation, run NIUBI Partition Editor to move the Unallocated space to behind C: drive and then you can expand C drive easily.

NIUBI Partition Editor integrated unique Roll-Back protection technology, which is able to roll back the server to the status before reszing automatically and rapidly if power failure or any other hardware issue occur, so you don’t need to worry about Operating System and all data safety. Furthermore, it is 30% – 300% faster than ANY other tools, because of its unique file-moving algorithm.

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