With the release of the Windows 10 Fall Creators Update later this year, Microsoft will be removing the ability to create ReFS volumes, to promote the new Windows 10 Pro for Workstations SKU.
After users began complaining that the latest OneDrive update doesn't work on non-NTFS file systems, Microsoft issued a statement today that said that this was indeed done deliberately.
The latest update for Microsoft's OneDrive sync client for Windows doesn't support any file systems other than NTFS. It's unclear if this is permanent, or if it will be fixed at a later date.
Microsoft has offered up more information about how the new file system designed for Windows 8, known as ReFS, will be handled in a new post on the official Windows 8 blog site.
The Protogon file system discovered in earlier builds of Windows 8 has been pulled. In its place is ReFS, a rejigging of the earlier Protogon system that can be accessed from the disk format utility.