Can't shrink C

Can’t shrink C drive in Windows Server 2008 Disk Management

Windows Server 2008 native Disk Management utility has Shrink Volume functionality, which is able to shrink C drive and any data volumes on the fly. However, sometimes it is unable to shrink partition C. This article shows why and what to do if you cannot shrink C: drive in Windows Server 2008 (R2) Disk Management.

Why cannot shrink C drive?

There are two common reasons and I’ll explain one by one.

Reason 1 Not enough space available

Press Windows and R key on keyboard to start Run, type diskmgmt.msc and press Enter.

Open disk management

Right click C drive and select Shrink Volume in Disk Management.

Shrink Volume

Enter the amount of space and click Shrink.

Enter amount

Disk Management report an error message: There is not enough space available on the disk(s) to complete this operation.

Error

Explanation: Disk Management use all available space by default, when I shrink C drive, the max available space is 47473MB. However, many types of files are writing into C drive continuously, so the max available space is less than 47474MB when clicking Shrink, of course I cannot shrink C drive with that value.

Solution: do not use the default value, enter a smaller amount, then you can shrink partition C without issue.

Reason 2 There’s unmovable files

Have you noticed the tip in the shrinking window? – You cannot shrink a volume beyond the point where any unmovable files are located.

Shrinking tips

Only part of the servers have such issue, but if there are any unmovable files, you can’t shrink C drive or can only shrink little space. For example: in my another test computer, there is still 7.53GB free space in C: drive, but the available space is 0 and the Shrink button is greyed out.

Can't shrink C

Explanation: For example, C drive is made up of 4 blocks, if the unmovable files are located in block 3, you cannot shrink C drive to block 2 or 1, although there is free space there.

Shrink C drive

Solution: The unmovable files include Paging file, Hibernation and other large files. You cannot locate these files and transfer to other partition manually. Instead, you need server partition software such as NIUBI Partition Editor.

What to do when unable to shrink C in Server 2008 DM?

Comparing with Server 2008 Disk Management, NIUBI Partition Editor has many benefits when shrinking a partition drive, for example:

  • Shrink C drive to minimum size because it can move all “unmovable” files.
  • Shrink C drive and generate Unallocated space on either left or right side.
  • Besides creating new volumes, Unallocated space can be used to extend other partitions in the same disk.
Download NIUBI Partition Editor, right click C drive and select “Resize/Move Volume”.

Shrink C drive

In the pop-up window,

If you drag the left border rightwards, Unallocated space will be generated on the left side of C drive.

Shrink C rightwards

If you drag the right border leftwards, Unallocated space will be generated on the right side of C drive.

Shrink C leftwards

Besides creating new volume, Unallocated space can be used to extend other partitions.

To extend the adjacent drive D:

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

Extend D

Step 2 Drag the left border leftwards to combine the Unallocated space.

Drag to extend Then drive D is extended to 50GB.

Drive D extended

To extend drive E:

Step 1 Right click D and select “Resize/Move Volume”, drag the middle position leftwards to move Unallocated space to the other side.

Move D

Click OK, 20GB Unallocated space is moved to the right side of drive D.

Unallocated moved

Step 2 Right click E and select “Resize/Move Volume” again, drag the left border leftwards to merge the Unallocated space, then drive E will be extended.

Drive E extended

Tip NIUBI Partition Editor is designed to work in its own virtual mode. The operations you do will be listed as pending on bottom left for preview. You may click Undo to cancel the unwanted operations or click Apply to modify real disk partitions.

In Summary

Comparing with previous Server 2003, Server 2008 Disk Management has the ability to change partition size with Shrink Volume and Extend Volume functionalities. However, sometimes you can’t shrink C drive with Server 2008 Disk Management as I explained above. The better option is running disk partition software such as NIUBI Partition Editor. It is able to shrink C drive without the limit of “unmovable” files. Unallocated space shrank of C can be used to extend any other partitions in the same disk. Of course, you can use it to do many other disk partition management operations.

Download

Solution – cannot/unable to shrink C drive in Windows Server 2008.
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