Several user reports — largely from Japan so far — say installing Windows 11’s August Secure Boot update (KB5063878) can lead to SSDs becoming inaccessible or files getting corrupted after heavy writes. If you use Windows 11 and rely on SSD storage, read this before you update.
What happened — quick facts
On August 12, Microsoft shipped Windows 11 update KB5063878, a Secure Boot-related patch. Shortly after the rollout, users began reporting instances where SSDs went missing from Windows after a period of heavy sequential writes. A reboot reportedly left Windows unable to read the partition and made SMART telemetry inaccessible in some cases.
- Update: KB5063878 — a Secure Boot certificate reset patch.
- Symptoms: Drive disappears from File Explorer, partition unreadable after reboot, SMART data inaccessible, possible system file corruption.
- Where reports appeared: Social posts and niche tech blogs (initially concentrated in Japan).
Which SSDs are mentioned
Based on aggregated user reports, several brands and controllers were called out (reported instances do not prove causation): Corsair, Phison-based drives, Fikwot, Maxio, and others. That list comes from community-collected reports and should be treated as anecdotal pending vendor or Microsoft validation.
Important: a brand appearing in reports does not guarantee every drive of that brand is affected — real-world behavior often depends on firmware version, controller, system BIOS, and workload pattern.
Potential technical cause (what experts suspect)
Analysis from independent outlets suggests the issue may stem from mishandled long sequential writes after the update — a scenario that could cause the OS to lose track of a drive. The concentration of reports from one region could reflect specific firmware/hardware combinations or localized update timing, rather than a strictly geographic bug.
Immediate alert — protect your data now
If your system has critical data on an SSD, back it up immediately. Do not rely on a single copy. If you haven’t installed KB5063878 yet, consider pausing Windows updates until there’s official confirmation of a fix.
Practical steps to protect yourself (recommended)
- Back up now: Copy important files to an external drive, NAS, or cloud backup. Create a full system image if possible.
- Pause updates (if you haven’t installed KB5063878): Settings → Windows Update → Pause updates. Resume once Microsoft releases a fixed update.
- If you already installed it: Keep Windows Update enabled so you receive a patch promptly. Disable heavy write workloads until a fix is confirmed.
- Collect diagnostic info: If you encounter the issue, gather Event Viewer logs, Windows Update history, and any SMART reports you can still access, then report to Microsoft (Feedback Hub) and your SSD vendor.
- Contact the SSD vendor: Check firmware updates and support advisories for your specific model; vendors may have mitigations or firmware patches.
Troubleshooting if your SSD becomes inaccessible
Quick troubleshooting checklist for affected drives (non-destructive first):
- Reboot once and check BIOS/UEFI to see if the drive is detected at firmware level.
- Try connecting the SSD to another machine or via a USB-to-SATA/NVMe adapter to confirm whether the drive itself is visible.
- If SMART is still readable, save the SMART report immediately (tools: CrystalDiskInfo, vendor utilities).
- Avoid repeated heavy writes or low-level formatting. If the partition is unreadable, refrain from tools that try to “fix” the disk without an image backup.
If the drive is still not recognized at the firmware level or SMART is unavailable, contact the drive manufacturer support and consider professional data recovery if the data is critical.
How to report the issue (help get a fix faster)
If you see this problem, reporting useful diagnostics speeds up investigation:
- Open Feedback Hub (Windows) → Report a problem. Attach screenshots, update history, and a concise timeline of what you did before failure.
- Collect Event Viewer logs under Windows Logs → System and export related errors/warnings.
- Include drive model, firmware version, system BIOS/UEFI version, and exact Windows build (Win + R → winver).
- Contact your SSD vendor support with the same information; they may request an RMA or provide firmware advice.
One- or two-step deeper insights
Why this looks especially serious: When an OS can no longer read a partition and SMART data disappears, it often means the drive has entered an unrecoverable internal state or the firmware/driver layer is failing to respond. That’s why immediate backups and vendor coordination matter.
Why defenders should care: Firmware-level or driver issues that appear after a Secure Boot update highlight how low-level security fixes can interact unexpectedly with storage stacks. This is a reminder that critical patches need broad QA across hardware vendors.
When will Microsoft fix it?
Microsoft has not (as of this writing) published a universal fix announcement. Typical steps are: (1) Microsoft investigates community reports, (2) identifies reproducer conditions, (3) works with hardware vendors, and (4) issues an updated cumulative/security patch. Keep Windows Update enabled if you’ve installed KB5063878 so updates arrive automatically.
Final takeaway
This appears to be a targeted but serious issue for users with certain SSDs, firmware versions, or workloads. The safest course of action is simple: back up now, pause updates if you haven’t installed the patch yet, and monitor official Microsoft and SSD vendor advisories. If you experience corruption or a drive disappearance after installing KB5063878, collect logs and report the problem to accelerate a fix.
Question for readers: Have you installed KB5063878 yet — and if so, did you notice any unusual SSD behavior? Share your experience in the comments below and consider reporting what you saw to Microsoft to help diagnostics.Keywords: KB5063878, Windows 11 update, SSD corruption, pause Windows update, SSD SMART
