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For some reason I can't activate a dynamic disk connected to my PC via a USB hard disk enclosure. It has activated previously without any problems.

When I check the event logs, I get this message every time I try to activate the disk:

dmio: Harddisk2 write error at block 2930277167: status 0xc0000015
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The reason appears here:

Dynamic disks are not supported for USB devices. The help and MSDN say this. You can fake around it in WinXP by attaching a drive to a SATA or IDE port, changing it to dynamic, then putting the drive in a USB enclosure. It appears they decided to enforce this restriction in Win7.

That's a drag, as it will make it difficult to mount a drive from a different machine on a USB chain, which you sometimes need to do to make repairs.

Microsoft is now enforcing the no-USB policy for Dynamic Disks.

If it is a single disk dynamic disk (not spanned or striped to another disk or set of disks), you MAY be able to convert it to a Basic Disk.

To change a dynamic disk back to a basic disk:

  1. Back up all the data on all the volumes on the disk you want to convert to a basic disk.
  2. Log on as Administrator or as a member of the Administrators group.
  3. Click Start, and then click Control Panel.
  4. Click Performance and Maintenance, click Administrative Tools, and then double-click Computer Management.
  5. In the left pane, click Disk Management.
  6. Right-click a volume on the dynamic disk that you want to change to a basic disk, and then click Delete Volume.
  7. Click Yes when you are prompted to delete the volume.
  8. Repeat steps 4 and 5 for each volume on the dynamic disk.
  9. After you have deleted all the volumes on the dynamic disk, right-click the dynamic disk that you want to change to a basic disk, and then click Convert to Basic Disk.

NOTE: You must right-click the gray area that contains the disk title on the left side of the Details pane. For example, right-click Disk 1.

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I'd run SpinRite on it to clear up any errors or bad sectors. I've saved several disks by using it, although I never use bad disks in a production environment after they've started giving errors.

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Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the product here, and provide the link for reference. – KronoS Jul 13 '12 at 14:14

I ran the manufacturers to test for errors, but it found none. I still can't access the disk, but I was able to use this tool to recover all of my data. I suspect the problem was caused by a dirty shutdown in Windows.

I just ended up reformatting the drive in the end

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