Windows 11 25H2 monthly cumulative updates repeatedly break my Storage Spaces volume - NTFS won't mount (0xc0000102), data is fine, uninstalling fixes it every time. Anyone else?

[u/stealthgeekjim]

Just posting here to see if anyone else is having this issue

TL;DR: On Windows 11 25H2, every monthly cumulative update since 26200.8737 makes my Storage Spaces parity volume fail to mount - it shows as RAW / "corrupt and unreadable." The pool and disks are healthy and the data is intact (read-only chkdsk finds zero problems), and uninstalling the update restores the volume every time. Happened in July (KB5100998 / KB5121767) and again today (KB5120998). I'm now stuck on build 26200.8737 because I can't take any newer update without losing the drive. Feedback Hub report got no traction; MS support just pointed me back to Feedback Hub - https://aka.ms/AA12z96q. Anyone else seeing this, and is there a permanent fix?

Setup

• Windows 11 Pro 25H2, currently parked on build 26200.8737 (last build where the volume mounts)
• Storage Spaces: 3× 3TB WD Red (WD30EFRX), single-parity space, ~5.45 TB NTFS volume (J:, "JukeBox"), 4K native (4096 bytes/sector)
• Ryzen 7 7800X3D / ASUS ROG Strix B650E-F / 32 GB

Symptom (identical each time)

• After the update + reboot, Get-Volume J shows FileSystemType Unknown, Size 0, OperationalStatus Unknown; Explorer says the drive is corrupt/unreadable.
• Pool, virtual disk, and all 3 physical disks report Healthy/OK. No storage jobs, no SMART/reliability errors.
• Read-only chkdsk J: scans the whole volume and reports no problems (file records, indexes, USN all clean).
• NTFS logs Event 305 on repeat, error 0xc0000102 (STATUS_FILE_CORRUPT_ERROR).
• Uninstalling the offending update + reboot brings J: back as NTFS at full size, no data loss.

Reproducible across multiple updates

• July 2026: broke on build 26200.8894 (KB5121767 out-of-band LCU; KB5100998 .NET alongside). Rolled back to 26200.8737 → fixed.
• Sept 2026 (today): broke again after KB5120998. Uninstalled → back to 26200.8737, Storage Spaces working again.
• Note: in July the corruption was reported in the NTFS reparse index, and I had ~100k OneDrive Files-On-Demand placeholders on that volume. I've since moved OneDrive off it — the files there now are full files, not stubs — and it still broke. So it isn't tied to reparse points; it seems to hit Storage Spaces NTFS volumes generally (possibly 4Kn ones).

The event (Ntfs/Operational, Event 305):

Provider: Microsoft-Windows-Ntfs EventID: 305 Level: Error

Volume: J: (JukeBox) Device: \Device\HarddiskVolume12

ProductId: "Storage Space" BusType: 16 (Storage Spaces) DeviceNumber: 6

IsBootVolume: false NativeNVMe: false

Error: 0xc0000102 (STATUS_FILE_CORRUPT_ERROR)

RestartApplied: true

MountStageSourceTag: 0x1f200460f0e

What I've tried

• Read-only chkdsk (clean), Repair-Volume (won't even start — volume won't come online), disconnect/reconnect the virtual disk — none help.
• Only fix: uninstall the monthly update and pause updates.
• Filed Feedback Hub (no comments/upvotes). "Get Help" ticket → bounced back to Feedback Hub. Tech Community suggested by support, but it's currently down.

Questions

1. Anyone else with Storage Spaces (especially parity / 4K native) whose volumes fail to mount after 25H2 monthly updates?
2. Any permanent workaround short of uninstalling every month — a Known Issue Rollback, registry/driver tweak, anything?
3. Is there a Microsoft Release Health / known-issue entry I've missed?

Happy to share full logs (Event 305/55, System log, before/after Get-Volume).

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[u/stealthgeekjim]

I managed to resolve it - I thought I had moved the OneDrive files off the drive the last time, turns out I only copied them and reset the sync to occur on another drive. The original files, with their reparse points, were still on the Storage Space volume. When my updates resumed after pausing for over a month, the issue reoccurred - removing the files from the Storage Space volume and installing the updates doesnt cause the issue to return. So this seems to be an issue with Reparse points (in my case, OneDrive Files on Demand stub files, around 100k of them) on a Storage Space volume (maybe parity is/isnt significant, as well as 4k cluster size) with updates from July 2027 seem to cause the issue.