I'm trying to setup a software RAID-1 at a new hosted server. It has two 3TB disks in and I've installed a fresh copy of Windows Server 2008 R2 Web Edition with SP1 on one of those disks.

A step-by-step tutorial that I found on the Internet says that I need to convert to dynamic disks first. Unfortunately this option is disabled in the Disk Management window. Please see this Screenshot.

What is going wrong here?

2 Answers 2


From Working with Basic and Dynamic Disks:

  • You can't convert drives that use sector sizes larger than 512 bytes. If the drive has large sector sizes, you'll need to reformat before converting.
  • You can't use dynamic disks on portable computers or with removable media. You can only configure these drives as basic drives with primary partitions.
  • You can't convert a disk if the system or boot partition is part of a spanned, striped, mirrored, or RAID-5 volume. You'll need to stop the spanning, mirroring, or striping before you convert.
  • You shouldn't convert a disk if it contains multiple installations of the Windows operating system. If you do, you might be able to start the computer only using Windows Server 2008.
  • You can convert disks with other types of partitions that are part of spanned, striped, mirrored, or RAID-5 volumes. These volumes become dynamic volumes of the same type. However, you must convert all drives in the set together.

Maybe point 1 in particular is one you should check? Aditionally Point 3 might be relevant(not sure if it only applies to software or hardware and software)


I had the same issue with a >2TB drive. I had to delete the volume(s)/partition(s) first, then the options to convert the disk became available. I was unable to find a non destructive way to do this unfortunately.

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