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Abel
Asked: 2010-07-21 03:08:49 +0800 CST

Resizing volume with DiskPart unsuccessful, while there's enough free space

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I have a physical disk with two partitions, an old OS partition (with MBR) of 296GB and a RECOVERY partition of 2048MB (a default DELL recovery partition), both are not in use. I have successfully resized the OS partition from 296GB to 174GB with the following command:

DISKPART> shrink

which shrinks to the maximum shrinkable space. However, the partition only uses 56GB and I want to create a partition of at least under 128GB (to be able to create a VHD of it). When I shrink again, I receive the following error:

DISKPART> shrink desired=50000

Virtual Disk Service error:
The specified shrink size is too big and will cause the volume to be
smaller than the minimum volume size.

According to this post I should defrag, which I did using several tools (open source UltraDefrag seemed to do the best job). It seems that all files are on top of the disk, but how can I check that for sure? And if not, how can I manually defrag/move files, to claim the largest possible consecutive free disk space?

Or: what should I do to shrink the volume to its current used size plus a bit?

(Note: I tried to create a new VHD with the CREATE VDISK command pointing to the oversized VHD for the source-parameter, but here too, the 128GB/137GiB limit prevents success, it seems. Mounting the VHD and shrinking it had exactly the same effect as doing it on the original physical disk, which is why I now try to first limit the physical partition size.)

windows partition defrag diskpart

4 Answers

  1. Best Answer

    It doesn't really matter whether its an OS disk or a data disk. In both cases, the middle of the disk is occupied by $MFTMirr which copies vital bits of the MFT Table. This file is unmovable, even though Microsoft made it available for moving since Windows XP.

    So far I have found only one tool that can reliably move these files: PerfectDisk. It has a free, fully-functional, thirty-days version. It can only move these Metadata and MFT files when in offline mode: Select Boot Time on its main tab and either reboot or, if possible, defrag in offline mode. After this, the command SHRINK worked as expected.

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  2. I am a dummy. and it took me 2 days to finally shrink my C: sys volume (WINDOWS 7). the solution I found is terribly simple.

    1. I downloaded the free app PerfectDisc, installed
    2. on 'Global Settings' I selected and ticked: PerfectDisk manages book and prefetch files'
    3. right click on C: - Drive preferences - select: 'Default optimization method' = 'Prep for Shrink' and 'Free Space search method' = 'Forward'
    4. now start defragging (play button)
    5. try also to turn on 'boot time defrag', and press the 'boot time defrag' button in the upper menu (requires restart)

    Good Luck everybody !!! what a relief

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  3. In my case I resolved "The specified shrink size is too big" on data disk by deleting files which had some tricky permissions (I copied those from MacOS some time ago).

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  4. PerfectDisc removed the "Prep for Shrink" feature for the trial edition.

    GParted Live will happily resize the partition, jus tbe sure you ran a proper chkdsk /f on the drive from Windows before booting GParted Live.

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