Hope the following review/summary of my recent experimenting with Microsoft Storage Spaces will be of use to others. Sorry if this is too 'verbose'... The steps I performed/show could be used in one of several scenarios...

1] If you physically remove a disk from a functioning Storage Space without going thru Storage Spaces in the Control Panel first. 'How to Remove Drive from Storage Pool for Storage Spaces in Windows 10'

2] If there is a failure of a disk in a Storage Space [two-way mirror]

3] If there is a failure of the computer hosting the Storage Space [again a two-way mirror].

In scenario 2 you can replace the failed disk and press-on. But if you want/need to get the files off the remaining 'good' disk or in the case of scenario 3 you have no other option, you can physically remove the disk from the computer and connect to another. In my case, moving a 2.5" SSD [Identified in the Desktop Pool as 'SamsungSSD2'] from a Windows 10 Home Desktop to a Windows 10 Home Laptop and connecting with USB 3.0 to 2.5” SATA III Hard Drive Adapter/Cable.

When connecting the 2.5" SSD to the laptop got a Notification 'Check Storage Spaces for issues'

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Windows displayed 'Microsoft Storage Space Device' in both Device Manager, Disk Manager and Explorer...

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All of the files stored on SSD2 were accessible thru Explorer. So at this point we can copy any/all the files from the Desktop's two-way mirror.

I can't speak to what would happen or the steps needed if you wanted to physically return the drive to the Desktop's original two-way mirror. The most straightforward option would be to build a new mirror on the Desktop from scratch and go from there.

At this point on the laptop, Windows treats the drive as a Storage Space [albeit in a 'Reduced resiliency' state]. The following steps will guide you thru how to get the SSD 'out' of Microsoft's Storage Space.

On the laptop, under Control Panel; Storage Spaces we are presented details about the Storage Pool as created on the Desktop, to include name of the Storage Space and the details about the Physical drives making up the original Two-way mirror. It happily finds SSD2, but SSD1 is missing. Hence the 'Warning' about 'Reduced resiliency...'. These details must be coming from somewhere on SSD2. I was not successful in finding out much about how/what is on a Storage Spaces Two-way mirror other than info on this Microsoft Blog in 2012

From here I selected 'Change Settings'; From there chose to 'Delete' the Two-way mirror Storage Space

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This deletes the Two-way mirror Storage Space, but we still end up with the two drives in the Pool. A simple matter to 'Delete Pool'

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And we end up here in the Control Panel...

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SSD2 now appears in Disk Management and Windows Explorer

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Of note... There were NO files from the Desktop Two-way mirror on SSD2 once we got to this point in the process!

Please, add/correct as needed since this was done in a bit of a rush.