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I am trying to shrink a volume on Windows 7 Professional using Disk Management but get the following error:

Virtual Disk Manager

The service cannot be started, either because it is disabled or because it has no enabled devices associated with it.

The disk I am trying to shrink is not the system disk. However as stated by Disk Management it is: Active, Primary Partition.

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up vote 6 down vote accepted

I've seen McAfee AV cause a situation where disks cannot be managed. I never figured out why but uninstalling resolved the issue.

I've also seen this issue when the Disk Defragmenter is disabled (for SSD) and turning it on temporarily allowed disk to be managed.

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Hm, the 'Disk Defragmenter' utility won't start at all. It is indeed disabled since I have an SSD. However the disk I try to shrink is not the SSD. Maybe I disabled the 'Disk Defragmenter' as a whole, then it is only how to enable it again... – Knarf May 4 '11 at 16:07
The 'defragsvc' service wont start... – Knarf May 4 '11 at 16:08
Starting 'Disk Defragmenter' service worked for me. – Nathan McDaniel Apr 9 '12 at 15:15
starting the service didn't do anything for me. – acme64 Jun 30 '12 at 5:26

Go to the start button, type "Services", click it (should have an icon of two gears), scroll down to "Disk Defragmenter". Change the startup type if you want to, and make sure the "Service status" is "Started". If not, make it so.

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Open a command prompt as administrator and run:

sc config defragsvc start= demand

enables you to start the defragsvc, beware if you have a schedule in effect.

sc start defragsvc

starts the defrag service so disk management can figure out how to reallocate files when you shrink the volume.

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I found that I also couldn't open Disk Management, as well as diskpart.

Open "Services", and scroll down to "Virtual Disk". If this is disabled, enable it with startup = manual. After I changed this, I was able to open Disk Management and diskpart.

This may work in conjunction with the Disk Defragmenter service, or this change may be all you need.

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