On August 12, 2025 , Microsoft released its monthly Patch Tuesday update for Windows 11 version 24H2 —specifically, KB5063878 (Build 26100.4946) .
Background: A Troubling Update
On August 12, 2025, Microsoft released its monthly Patch Tuesday update for Windows 11 version 24H2—specifically, KB5063878 (Build 26100.4946).
Shortly after, users began reporting alarming storage issues: SSDs disappearing from Windows, input/output (I/O) errors, and data becoming inaccessible after large file transfers. Microsoft has since confirmed the reports and is working with hardware vendors to investigate.
Symptoms & What Happens
Affected users observed the following behavior:
- During large write operations (≥ 50 GB) on drives more than 60% full, SSDs vanish from File Explorer, Device Manager, and sometimes even BIOS.
- Some drives reappear after a reboot, but others show partitions as RAW, making data recovery difficult or impossible.
- Early testing shows the issue is more frequent on Phison-based and DRAM-less SSDs, though it is not exclusive to them.
In extreme cases, users lost access to critical data.
Microsoft’s Response
- Microsoft acknowledged the reports and is collecting feedback through the Feedback Hub.
- Phison, a major SSD controller maker, is also investigating.
- Meanwhile, another patch (KB5063875) broke recovery tools like “Reset this PC”, prompting Microsoft to issue an out-of-band (OOB) fix KB5066189.
Clearly, this August update batch has been one of the more problematic ones in recent memory.
What You Should Do Right Now
1. Avoid Large File Transfers
Break large jobs (like game installs or backups) into smaller chunks until a fix arrives.
2. Delay the KB5063878 Update
If you haven’t updated yet, consider pausing Windows Update to avoid SSD risks.
3. Backup Your Data Immediately
Follow the 3-2-1 rule:
- 3 copies of your files
- 2 different storage types (SSD + external HDD/cloud)
- 1 copy offsite
4. Apply KB5066189 if Needed
If your recovery/reset options are broken after KB5063875, install Microsoft’s emergency fix.
5. Report the Issue
Submit reports via Feedback Hub—the more data Microsoft receives, the faster a permanent fix will come.
Quick Summary
| Issue | Cause (August 2025) | What To Do |
|---|---|---|
| SSDs disappearing / I/O errors | KB5063878 + heavy writes | Avoid large transfers, backup data |
| Recovery tools broken | KB5063875 | Install OOB patch KB5066189 |
| Fix status | Microsoft + partners investigating | Wait for official patch, report issues |
Wrapping Up
While not everyone is affected, the risk of SSD corruption and data loss makes this bug serious. Until Microsoft provides a confirmed fix, the best approach is caution and backups.
Stay safe—and don’t let your SSD vanish into thin air.