Forum Discussion
ReFS volume inaccessible after update from Windows 10 22H2 to Windows 11 23H2
Since opening this thread in December, I'd like to share two "solutions" (workarounds):
1) As mentioned before, I attached the ReFS 3.4 volume which wouldn't read on Windows 11, to a Windows Server 2022 system, which auto-updated it to ReFS 3.7. Moving the disks back to the Windows 11 system, I can confirm that they now work fine. Storage Spaces on Windows 11 prompted to upgrade the pool, but the data was readable both before and after this upgrade. The ReFS version remained unchanged at 3.7. This solution does not require purchasing new disks, but it does require access to a Windows Server 2022 system.
2) The other method is to get new disks and copy the data, using an OS version like Windows 10, which can read the ReFS 3.4 volume which became unreadable after the upgrade to Windows 11.
Hi all,
When using ReFS for internal drives, please consider to disable ReFS upgrade before upgrading to Windows 11 23H2 or 24H2.
Important: Do not use ReFS for Windows OS drives or external / removeable drives.
How-to temporary disable ReFS upgrades:
It needs to be set before connecting an "online / mounted" volume to a newer OS.
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem]
"RefsDisableVolumeUpgrade"=dword:00000001
Effect of this setting:
Mounting a ReFS volume to a (newer) OS, with this registry key set - for this OS instance - will prevent upgrading to the lastest ReFS metadata version.
If you are using multi-boot, it needs to be the same for all OSes
Reasons:
On this thread, but also on GitHub as well as the previous gist, there are different reports about the issue.
There's a risk of duplicate reports, however there are also singular reports for "Windows Server 2025 / Azure Local 23H2" based issues. Reports here and on gist focusing on Windows Client OS.
Generally, I sense a number of issue reports with the upgrade. These either take longer than expected or ReFS upgrade worked but files still cannot be read / accessed correctly.
Setting up the registry key will not upgrade your ReFS. Downgrade or rollback to previous Windows OS version are possible.
Next steps:
We would require support requests and reproducible conditions, quite hard as one needs to simulate quite some fair amount of files and folders.
With empty or near empty small drives, I doubt this is going to be reproducible.
Possible issues:
Disable ReFS upgrades gives peace of mind at the moment. Yet can cause outlier configs if people forget to disable the setting.
Means: ReFS version and OS version no longer match.
Reverting the change:
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem]
"RefsDisableVolumeUpgrade"=dword:00000000Please mind, that ReFS upgrade will cause read and writes during the upgrade time. There's no progress visible. The upgrade takes time based on media type, like HDD vs NVMe, size, and number of TB of files.
Be mindful: There is no command to initiate the ReFS upgrade, monitor or revert (downgrade) ReFS. Mind when using Spaces Spaces, do not upgrade the Pool if you want to roll back to an older release or need to access the Pool from different OS Versions (multi-boot).
Recommendation for reporting issues:
Before upgrading
Include the Windows version, build and Edition of the OS before upgrading to 23H2 /24H2. Find these with get-computerinfo or PC-Infos in settings app
Include information or Screenshots from Get-Volume
Include Information about ReFS version
fsutil fsinfo refsinfo DriveLetter:Windows 11 22H2, 23H2 and 24H2 do not share the same versions of ReFS.
Do you use Windows default storage drivers?
What's the amount of files, folders and TB of data?
Do you use AMD or Intel RAID / VMD?
Do you use Storage Spaces?
Post upgrade
Include the same information.
If ReFS upgrade is not disabled, please let it work in the background to upgrade. Avoid reboots and other changes, storage driver updates etc.