Cannot extend C

Cannot/Unable to extend C drive on Windows Server 2016

Windows Server 2016 provides native Extend Volume functionality in Disk Management to increase size of allocated partition, but many people feedback that they cannot extend C drive after shrinking D or other partitions. In this article, I’ll explain why you unable to extend C drive in Server 2016 and introduce 1-step solution to fix this issue.

Why unable to extend C drive?

First you should know: a 160GB hard disk can’t be increased to 200GB, thus, before extending a drive you must delete or shrink another one to get Unallocated space. Unlike Free space that is inside of an allocated partition, Unallocated space is not belong to any partition. After deleting a partition, all disk space of it will be converted to Unallocated. By shrinking a partition, only part of the Free space will be converted to Unallocated.

That means, you cannot extend C drive in Server 2016 Disk Management if you do not delete or shrink drive D.

Extend Volume disabled

To most of the servers, programs and/or part of Windows services are running from drive D, so it’s a bad idea to delete it. The only choice is by shrinking it. Many people did this, but still cannot expand C drive, why?

The truth Extend Volume is available only when there is adjacent Unallocated space on the right side of the partition that you want to extend.

When you shrinking drive D: with another Shrink Volume functionality, you can only enter an amount of space to shrink, there is no other options.

Enter amount

After clicking Shrink, Unallocated space is produced on the right side of D. As you see, the 20GB Unallocated space is nonadjacent to drive C, of course you cannot extend it.

Extend Volume greyed out

What to do when cannot extend C drive?

In this situation, you need a tool to move the Unallocated space to the other side, then Extend Volume is activated for C drive. Then how to move the space?

Download NIUBI Partition Editor, right click partition D and select “Resize/Move Volume”.

NIUBI Partition Editor

Drag the middle position rightwards in the pop-up window.

Move Unallocated

Click OK, Unallocated space is moved to the left side of D. Click “Apply” on top left to execute.

Tips To avoid mistake, the operation you do will be listed as pending for preview, to modify real disk partition, you need to click Apply to confirm.

Unallocated moved

Check in Disk Management after it complete. As you see, Unallocated space is moved to the left side and Extend Volume is enabled for C drive.

Tips If Disk Management is not closed while running NIUBI, you need to click Action > Refresh or restart Disk Management to show the modified partitions.

Extend Volume activated

Now you may either use DM or NIUBI to expand C drive. To to this with NIUBI, you still just need 1 step to drag.

Right click C drive and select “Resize/Move Volume” again, drag the right border rightwards to combine the Unallocated space.

Extend C drive

Click OK, C drive is extended to 50GB. (Remember to click Apply)

C drive extended

Be caution of data safety and server offline

It seems to be an easy task to move Unallocated space and extend C drive in Windows Server 2016, but there is system and data damage risk if you use some unreliable disk partition software. During these operations, all parameters of drive C and D should be modified, system information should be updated, all files in drive D should be moved to new locations. Any slight error will cause boot failure and/or data loss.

Better than other tools, NIUBI Partition Editor is integrated 1 Second Rollback technology to ensure system and data intact. If any software or hardware issue occur, it automatically revert the server to original status in a flash. This is the reason why it is recommended.

Furthermore, if there are some programs or Windows services in drive D cannot be closed, the moving operation requires server reboot to execute. Thanks to the Hot-Resize technology, NIUBI has less probability to reboot. If rebooting is unavoidable, NIUBI can finish with less time. Because of its unique file-moving algorithm, it is 30% to 300% faster.

Tips The pending operation marked as Check can be done in desktop, the ones marked as Reboot requires rebooting.

In Summary

Windows native Disk Management neither can produce Unallocated space on the left, nor move partition, which cause you cannot extend C drive in Server 2016. In this situation, you need a tool to move Unallocated space to the other side, and then this problem can be solved. To do this, NIUBI Partition Editor can help you easily and safely.