I am setting up a new computer with two Crucial m500 960GB SSD drives.  I have Windows 8.1 Pro installed on the first drive. I am trying to mirror it to the second drive (using Windows Disk Management), but I get the error below.  I can't find anything online regarding this error.  Bitlocker is not enabled on the drive.  I tried turning off UEFI Secure Boot, but that didn't help either.  There is the System Reserved drive created during the Windows install, but I wouldn't expect that to cause this problem.  Any ideas?

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Virtual Disk Manager
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The disk could not be converted to dynamic because security is enabled on one or more partitions.  
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OK   
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Hi,

According to your description, I suggest we try safe mode to check the result.

Meanwhile,I would to know if you installed other security software on your PC.

Regards,

I just tried converting the disk to dynamic in safe mode, and I got the same result.  Any other ideas?

I never figured out a solution to this issue, but to work around it I ended up using my motherboard RAID instead of dynamic disks.

• Marked as answer by Kate LiMicrosoft contingent staff, Moderator Thursday, February 06, 2014 2:18 AM

Just replying to this as I had the exact same issue and this is the only thread that comes up on it.

This appears to be an issue when attempting to convert GPT based disks to Dynamic, if you switch to MBR you are able to convert to Dynamic fine - not sure if this is an actual limitation or just a bug but hopefully that helps someone else out.