Failed to reduce D drive to extend C drive - What to do?

Many users encountered the same situation that failed to reduce D drive to extend C drive in Disk Management. They are wondering why this is happening and how to solve this problem. Stop worrying, this post will tell them the answers.

All disk partitions are allocated while building the Server or PC, but things are changing, original partition size may not fit for your needs, the typical example is that system C: drive is full or running out of space. Originally, you have to start over, backup, delete, recreate and restore, what a annoying and time-consuming work. Especially for a server, no one bear it offline for one more minutes.

Shrink D: and expand C: is an easier and faster way to solve this problem.

Unfortunately, the solution failed happens all the time.

In this post, I will explain why Windows Disk Management doesn't allow you to extend C drive by taking space from D drive as well as show how to fix the issue with a professional partition manager.

How to Reduce D Drive to Extend C Drive

Since you want to extend C drive Windows, to make your computer boot normally after reducing D drive to extend C drive, I suggest using MiniTool Partition Wizard Bootable Edition.

If you are a home user, the MiniTool Partition Wizard Pro Edition can totally meet your needs. Click the button below to get this program.

At first, you need to create a bootable media. Then shut download your computer. After that, make your computer enter BIOS and set your computer to boot from the bootable media. Next, you need to wait a while, and this tool will enter to the main interface of MiniTool Partition Wizard automatically.

Step 1: Select the C partition and choose a preferred way to start extending C drive by taking space from D drive:

Choose Extend after clicking Partition from the upper menu bar, choose Extend Partition from the left action panel under Change Partition, or click Extend after right-clicking on the C drive.


Step 2: Select D drive to take free space from the drop-down menu of Take Free Space from option and drag sliding handle to decide how much free space to take. Then, click OK to return to the main window.


Step 3: Now, users can see the changes of these two partitions on the main interface intuitively, but this is just a preview. If users want to save this, don’t forget to click the Apply button in the top left corner. Then the C drive space is increased successfully by reducing D drive.


Besides, this is not the only solution to extend C drive from taking free space from D drive. Move/Resize Partition can also achieve the purpose which by using another feature via this tool.

Why Reduced D Drive but Can't Extend C in Windows Disk Management

It's largely because space got from D drive is not right contiguous to drive C. Or the file system is not NTFS or RAW.

The people who are quite familiar with Windows Disk Management utility know Shrink Volume feature can only create an unallocated or free space after its source partition, and the very space can only be used to create a new drive or extend the source partition itself.

However, the Extend Volume feature is available only when there is contiguous unallocated or free space on the right side.

So, these limitations mentioned above are the reasons why you can't reduce D drive to extend C drive in Windows Disk Management. Possible reasons for Extend Volume grayed out are shown here, and you will be given corresponding solutions at the same time.

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