I am attempting to split a two-way mirror storage space. There are two physical disks in the storage space. The idea is to keep the contents of the storage space, while going back to NTFS. I do not have the additional disk capacity to copy over the contents of the storage somewhere else while I remove the storage space entirely.

Thus, I retired one of the two disks and attempted to format the retired disk. Unfortunately, when the disk is retired, it is still part of the storage space. I then attempted to repair the storage space, but it will complain there is not enough space and demands a HDD replacement to keep the two-way mirror intact. Since Windows does not seem to let me touch the HDD that's still in the storage space, I'm completely stuck at this point.

How can I force the HDD out of the storage space to format it as NTFS and copy the files over from the storage space? Or is there another way to accomplish my goal?

  • You could turn the machine off, remove the disk, nuke it via any number of ways, reinsert it - I'm presuming windows will let you access the files even with one disk down/missing? Jun 28 '17 at 17:44
  • @djsmiley2k I believe it does some sort of serial ID detection to figure "Hey, this is my disk, I'm going to completely hide it from you and use it as such". It does allow access. If anyone can confirm this theory, I'll just pop into Ubuntu and use gparted to nuke it into oblivion. Good thought!
    – Deathspike
    Jun 28 '17 at 18:12

No, is not possible to keep the content while going back.

Once you go in, there is no way out.

source: https://answers.microsoft.com/en-us/windows/forum/windows_10-files/i-do-not-want-to-use-storage-spaces-anymore-is/dfae5e86-271d-440a-98b8-6d057909db20

2021 at the stage of the art,

Folks at Microsoft did not include a "Move Out" button option for moving the data out or preserving the data in the disk. The "format" will delete data, "delete" will delete and taking and "prepare for removal" will also delete the data on the disk.


In case of Storage Spaces fails and it does,


there are few options: Copy and paste, or Move past content from one drive to another. Clone is not an option.

PS: If you copy and past you will lose data as for example date created timestamp. And Moving at a "file-level" option, a full big disk is not a real option because is dangerous and unreliable. Probably will fail and create more problems having some content on one side and some on the other recursive each time you move.


There is the complex Microsoft robocopy option that does not make a sum check or final comparison does not guarantee to work. You can youse a compare software after the process but will be very time-consuming for a large amount of data.


Robocopy: A long standing issue with Robocopy means that if you back up from the root folder of a drive [ eg, robocopy d:\ b:\d-backup\ ....], the destination files will be given attributes including SH. This means that they will be invisible to normal access (including DIR in cmd.exe). To fix this, add "/a-:SH" to the robocopy command line - or do an ATTRIB command to remove them afterwards. Wikipedia

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