# Microsoft ReFS support updates

> Live situation record from CLSTR: https://clstr.news/situations/microsoft-refs-support-updates
> Updated: 2026-10-18T20:57:11.000Z. Sources: 9. Developments: 2.

Microsoft is modifying how its Resilient File System (ReFS) functions across different Windows environments. For Windows 10 and Windows 11, the company is restricting ReFS support on removable media, such as USB drives and external SSDs. An auditing phase began with October 2026 cumulative updates, which logs event ID 524 when ReFS volumes are connected to removable devices. By January 2027, Microsoft intends to move to a mandatory enforcement phase where mounting ReFS volumes on removable media will be blocked by default, though administrators can bypass this via group policy or the Registry.

Simultaneously, Microsoft is expanding ReFS capabilities for Windows Server 2025. Through the Windows Server Insider Preview, ReFS can now serve as a boot file system, allowing the operating system to be installed directly onto an ReFS volume. This update aims to integrate ReFS more deeply into server production by utilizing its data integrity features during the boot process.

## Timeline

### 2026-10-18: Microsoft to block ReFS on Windows 11 USB drives by 2027

Microsoft will begin blocking the default mounting of ReFS-formatted USB drives and external storage on Windows 11 by January 2027, following an initial audit phase starting in late 2026.

4 sources. https://clstr.news/cluster/microsoft-to-block-refs-on-windows-11-usb-drives-by-2027

### 2026-10-14: Microsoft updates ReFS support for Windows 10, 11 and Server 2025

Microsoft is restricting ReFS support on removable media for Windows 10 and 11 by 2027, while simultaneously enabling ReFS as a bootable file system for Windows Server 2025.

5 sources. https://clstr.news/cluster/microsoft-updates-refs-support-for-windows-10-11-and-server-2025

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Cite as: Microsoft ReFS support updates. CLSTR, https://clstr.news/situations/microsoft-refs-support-updates