The file system of the Windows operating system is NTFS, whether you’re running it on a desktop/laptop or server. It’s the only file system Windows can run on and boot from, at least officially, so you’re not even given a choice of file systems for the boot volume like you are on, say, desktop Linux. That’s about to change, though: Microsoft has finally announced that Windows Server will be able to boot from ReFS.
We’re excited to announce that Resilient File System (ReFS) boot support is now available for Windows Server Insiders in Insider Preview builds. For the first time, you can install and boot Windows Server on an ReFS-formatted boot volume directly through the setup UI. With ReFS boot, you can finally bring modern resilience, scalability, and performance to your server’s most critical volume — the OS boot volume.
↫ chcurlet-msft at Microsoft’s Tech Community
Without diving too much into the weeds, ReFS can roughly be seen as Microsoft’s answer to modern file systems like ZFS and Btrfs, with comparable design goals and feature sets. It’s been around since 2012, but only for Windows Server, and with every Windows Server release since, the company has improved performance, added new features, and fixed bugs. Now, in 2026, it seems Microsoft thinks ReFS is ready to be used as a bootable file system for Windows Server.
If you want to try this for yourself, you need to be a Windows Insider and make sure you have Windows Server build 29531.1000.260206-1841 or newer. During installation, the Windows installer will ask you to choose between NTFS and ReFS; the rest of the installation process will be pretty much the same as before. Now all we need is to wait for ReFS to become an option on client versions of Windows too, which would mark – arguably – only the second time in history Windows transitioned from one default filesystem to the another.
3’rd if you count the move from FAT16 to FAT32.
NTFS has just been a reliable well designed FS from the very start, benefiting from the experience several of its developers gained while working at DEC on VMS and Files-11, and it was constantly updated with new features.
Windows for Workstations also supports ReFS (not for boot, ofc). I actually use it on my 2x nvme ThinkPad P1 in mirror-mode on top of virtual block devices to create a 256gb volume. The only poop is that you have to double click both VHD files after booting to get Windows to mount the volume. I couldn’t figure out how to get Windows to boot ReFS on top of VHDs on boot.
Microsoft always finds ways of screwing up everything. Without file data integrity checking by default ReFS is not really competing with ZFS or Btrfs. It’s more like XFS is to ext4. Also the optional functionality there are enough horror stories that it can’t be trusted. Typical Microsoft.