Windows 10: How to remove spanning from two physical disk drives

I have two physical 5 TB disk drives that I was attempting to use to create a mirrored storage configuration. I followed the directions that I found on the internet and all was going as expected until the last step which was to create the final mirror configuration. At that point I got an error message that said something to the effect that the feature was not compatible with something. I went back and tried again with the same results. It was not a great idea but for several hours I've been trying different things and then trying to undo them. At the moment I have a Disk 4, Basic, 9314.2

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Reclaiming a Formerly Spanned Drive

The problem is that Disk Management will only let me create a 2TB volume. But the original span consisted of two 5TB drives, one of which died. Disk Management shows the capacity of the remaining drive to be the size of the two spanned drives, not the size of the physical drive. Everything above 2TB shows as Unallocated, and all options for that unallocated space are greyed out, as is the Extend Volume option for the 2TB volume.

The only other option that is not greyed out is the Convert to GPT Disk, which is enabled after I delete the 2TB volume. But when I try that I get the "not enough physical disks" error. Apparently, DM thinks that the drive is still part of a span. How do I unspan it?

 

Reclaiming a Formerly Spanned Drive

I have a drive that was once part of a spanned pair (yeah, I know, big mistake, lesson learned) and I want to go back to using it as a single drive. When I load Disk Management (Windows 10) it shows the size of the drive to be the original spanned volume size, not the drive's physical size. When I try to do anything in Disk Management, it just tells me "There were not enough physical disks to complete the requested operation." I tried using diskpart (clean, create, convert, whatever) with no joy. How do I correct this? Is there a way to reset this drive to factory defaults?

 

Reclaiming a Formerly Spanned Drive

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