How to shrink volume in Windows Server 2012 (R2)?

Microsoft added “Shrink Volume” and “Extend Volume” features in the built-in Disk Management console from previous edition Windows Server 2008. Windows Server 2012 inherited these features, so you can do part of disk drive resizing operations. If you forget to create more partitions when installing Windows Server 2012, all disk space will be used by the system C: drive. As we know, it is not a good idea to use single system partition and put everything into it. With Shrink Volume function, you can decrease the C drive partition size to generate Unallocated space, and then you can create more volumes easily. However, not every drive can be shrank via “Shrink Volume”, in some cases little space can be shrank from the OS partition. In this article, I’ll introduce how to shrink volume in Windows Server 2012 with built-in Disk Management and 3rd party software.

How to shrink volume under Disk Management?

Step 1: Open Windows Server 2012 Disk Management (right-click Windows on bottom left and then select Disk Management).

Step 2: Right click the drive you want to shrink and select “Shrink Volume“.

Step 3: Enter the amount of space to shrink. The default amount is all available size. Click Shrink to continue. This partition will be shrank in a short time.

In some cases, you can only shrink little space, as the note says “You cannot shrink a volume beyond the point where unmovable files are located.”  What does that mean?

Limitation of Server 2012 Disk Management

From Microsoft help document, when you shrink a partition, certain files (for example, the paging file or the shadow copy storage area) cannot be automatically relocated and you cannot decrease the allocated space beyond the point where the unmovable files are located. If the shrink operation fails, check the Application Log for Event 259, which will identify the unmovable file.

  1. Assume the drive you want to shrink is consist of 4 blocks – A, B, C and D, the unmovable file is in block C. You cannot shrink volume to block A or B, even if there is free space. 3rd-party tool such as NIUBI Partition Editor is able to move the “unmovable” files, this is the reason why it shrink much more space than Disk Management.
  2. Another shortage is related to extend volume, some people try to shrink D with Shrink Volume and then expand c drive Extend Volume in Disk Management. It is impossible, only when there is continuous space at the right side of C drive, you can extend it, but the free space shrank from D is not.

How to shrink volume with partition software

The aim to shrink volume in Windows Server 2012 is different:

  • If you created C drive too large and want to shrink it to create more drives, follow the steps in section 1.
  • If you want to shrink D to expand C, follow the steps in section 2.

Section 1 – Shrink volume to create new drive

Step1: Download NIUBI Partition Editor, right click C drive and select “Resize/Move Volume“.

Shrink c drive

Step2: In the pop-up window, drag the right border leftwards.

Shrink volume

The Unallocated space will be created at the right side of C: drive, which can be used to create new volumes.

C drive shrank

Step 3: Right click the Unallocated space and select “Create Volume“.

Create volume

Step 4: In the pop-up window, click OK to use all Unallocated space, as well as the default settings. Instead, you can do these operations:

  1. Add label (name) to this new volume
  2. Select a drive letter
  3. Select File System and cluster size
  4. Select to create this drive as Logical or Primary
  5. Drag either border to change the partition size.

New volume settings

Step 5: Click OK and back to the main window, click Apply on top left to execute, done.

Section 2 – Shrink volume to extend other drive

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

Drag to resize

Step 2: In the pop-up window, drag the left border rightwards to generate free Unallocated space.

Shrink volume

You may also input a value for the Unallocated space directly.

Drag to resize

Click OK and back to the main window, where you’ll see 20GB Unallocated space created behind C: drive.

Unallocated space

Step 3: Drag the right border rightwards to hold the Unallocated space.

Drag to resize

Hold unallocated space

Step 4: Click OK and back to the main window, where you’ll see C drive extended to 60GB by taking 20GB free space from D. Press Apply on top left to execute, done!

Partition resized

Video guide to shrink and extend volume on Server 2012


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