By Emily / Last Updated August 12, 2020

Wish to reduce D drive to extend C drive in Server

“My Server 2012 C drive was almost full and started to make the computer run a bit slow. But my D drive has lots of free space unused. So my question is if I shrink my d drive and extend the c drive with the un-partitioned space? Thank you!”

Most Windows users might have met the problem that system C drive is running out of space if the system drive is not large enough and optimized regularly. What to do when C drive is almost full? I believe nobody wants to reinstall OS and recreate a system drive from scratch. So many users want to reduce D drive to extend C drive with the unallocated space without losing any important data. But it is possible and feasible to transfer free space from D drive to C drive?

Cannot extend C drive after shrinking D in Disk Management- Why?

When you have shrunk D drive and then tried to extend C drive in Windows Server Disk Management, you might find the “Extend Volume” disabled on the system C drive. Why cannot you extend C drive with the unallocated space from shrinking D partition?

Extend Volume Greyed Out Server 2012

That’s because Disk Management can only extend a partition when there is adjacent unallocated space. When you shrink D drive, the unallocated space will locate after the D partition, but not C drive. So even if there is unallocated space, you cannot use it to extend C drive. In this case, the only workaround is to delete the partition, which is right adjacent to C drive (like D drive), to get contiguous unallocated space, then the “Extend Volume” will be clickable. (WARNING: deleting partition will make you lose everything on the partition, so please make a backup firstly.)

Note: the Disk Management can only extend NTFS partition. If your system drive is formatted with FAT32 or exFAT, you can not extend it either even if it is followed by adjacent unallocated space.

Successfully shrink D drive and extend C drive in Server

If you cannot reduce D drive to extend C drive in Server Disk Management due to its limitation, and don’t want to delete D drive directly, you can switch to a third-party Server partition manager like AOMEI Partition Assistant Server. Much better than Disk Management, this software can allow you to:

firstly move non-adjacent unallocated space right behind the C drive, and then extend C drive successfully.
②directly merge unallocated space (no matter where it is on the disk) into the C drive by 3 steps.
③directly assign or transfer some free space from D drive to C drive by 3 steps.

In a nutshell, it provides you with 3 ways to avoid the issue “cannot reduce D drive to extend C drive” in Disk Management. Below we will demonstrate how to shrink D and extend C drive with the “Move Partition” feature in detail. Before proceeding, you can click the button to free download the Demo version.

Step 1. Install and run the AOMEI Partition Assistant Server. Right-click the D drive and choose “Resize Partition”.

Resize A Partition

Step 2. In the new window, drag the bar to the left side to shrink D drive, and drag the entire partition to the rightward to move it, finally, click “OK”.

Move And Resize Partition

Step 3. Then you can see the unallocated space is right after C drive. Now right click C drive and choose “Resize Partition”.

Resize Destination Partition

Step 4. Drag the bar to the rightward to extend C drive with the unallocated space and click “OK”.

Extend Partition Size

Step 5. Back to the main interface, click “Apply” and “Proceed” to commit the pending operation.

Proceed

This is how to shrink D drive, move D drive, and extend C drive with unallocated space. It requires at least 5 steps. To make it easier, we recommend using the “Merge Partitions” feature: right-click the C drive and select “Merge Partitions”, tick unallocated space and click “OK”, and finally hit on “Apply” > “Proceed” to commit the pending operation.

Choose Unallocated Space

If you have not shrunk the D drive yet, and no unallocated space available to extend C drive, you can try the “Allocate Free Space” function, which can directly transfer free space from d drive to c drive.

Step 1. Right-click the D drive and select “Allocate Free Space”.

Allocate Free Space

Step 2. Now, you can assign a certain amount of free space (size in GB) from D drive to C drive, then click “OK”.

Allocate Free Space From D To C Drive

Step 3. Back to the main interface, click “Apply” and “Proceed” to commit the pending operation.

Note: AOMEI Partition Assistant Server is compatible with all Windows Server operating systems and Windows 10, 8, 7, XP, Vista, so these methods can apply to shrink D drive to extend C drive in Server 2008/2012/2016/2019 and Windows 10/8/7.

Summary

So, when you fail to reduce D drive to extend C drive via Server Disk Management, AOMEI Partition Assistant Server is a great alternative. Besides the above sure-fire ways to successfully shrink D drive and extend C drive, it also comes with “Extend Partition Wizard”, permitting you to extend NTFS system partition without rebooting Server and PC. To install such an amazing partition manager in unlimited PCs and Servers, you can try AOMEI Partition Assistant Unlimited.