ReFS volumes on removable media: enforcement phase
WindowsWindows Server
- Who is affected
- Devices that use ReFS on externally attached or removable storage. The October 2026 update started the audit phase; the January 2027 update can block affected volumes.
- What to do
- Review the audit events added by the October 2026 update to find external ReFS volumes.
- Reformat or move data off unsupported external ReFS configurations before January 2027.
- Source
Hardening changes for ReFS volumes on removable media“January 2027 Windows security update (Enforcement phase)”
Windows message center (Windows release health, Microsoft Learn)
Checked 9 Nov 2026 Link to this deadline