Are you aware of ReFS, Microsoft’s next-generation file system for Windows? I’m sure the average OSNews reader is, but I really wonder how many people are using it out in the wider world, even though Microsoft keeps improving it. Since earlier this year, Windows Server and Windows 11 can boot from ReFS volumes, and it’s used by Windows’ Dev Drive feature as well.
What Microsoft doesn’t seem to want, though, is people using ReFS on removable drives.
Starting with Windows updates released on and after October 13, 2026, Microsoft is making hardening changes to the Resilient File System (ReFS).
This article describes Windows hardening changes for ReFS volumes that are mounted from removable media. ReFS on removable media, such as a USB disk, is not a supported configuration. The changes add auditing and enforcement controls that help administrators identify these volumes and prevent them from being mounted.
↫ Microsoft Knowledge Base article
I’m oddly fascinated by this. Apparently, there are enough people out there trying to use ReFS on removable media to warrant the above auditing and enforcement controls, which is fascinating in an of itself. On top of that, using ReFS on removable media is apparently also dangerous enough – which raises the question of why, exactly, it’s so dangerous in the first place. Microsoft doesn’t really explain itself here, other than saying it’s “not a supported configuration”.
I wonder if and when Microsoft will move from NTFS to ReFS as the default file system for new Windows installations. It’s been around for quite a while now, and there’s no denying that competing operating systems, especially in the server space, have file systems that are far superior to NTFS (like Btrfs, ZFS, and others), and I’m assuming Microsoft would love to catch up. It’s been a long time since Microsoft changed Windows’ default file system, however, and with the massive number of people using Windows, it’s not something to take lightly.
Then again, Apple migrated hundreds of millions of iPhones, iPads, and Macs to a brand new file system without anybody noticing a thing, and as far as I can recall, without any problems.
