SSD Issues After Windows 11 Update: Coincidence or Real Bug?

Since mid-August, multiple users have reported SSD failures after installing the security update KB5063878 on Windows 11. Disks disappearing, files getting corrupted, and ineffective reboots—these issues have been widely reported, especially in Japan. Microsoft has opened an investigation, along with certain SSD controller manufacturers like Phison, to understand the root cause of these incidents.

However, despite the increasing number of reports, Microsoft is trying to reassure users by stating that no direct link has been found between the update and the reported problems. So, is this simply a coincidence or a real issue that slipped under the radar? Let’s break it down.

Alarming Reports But Difficult to Reproduce

The story began with messages posted on social media, primarily in Japan, where users reported sudden SSD disappearance after large data transfers. The incidents were mainly related to transferring large files (over 50GB) onto disks filled more than 60%, on machines running Windows 11 24H2, updated with security patch KB5063878.

Some users were able to recover their disk after a reboot, while others were not so lucky. And it wasn’t just obscure models being affected. Popular SSDs like the Corsair Force MP600, SanDisk Extreme Pro, and even Kioxia models were regularly mentioned, often equipped with InnoGrit or Phison controllers.

As the reports multiplied, Microsoft quickly announced it was “investigating the situation” and invited affected users to submit feedback via the Feedback Hub or contact professional support. However, despite this request, very few official reports seem to have reached Redmond’s teams.

Microsoft Reassures: No Link to Update

After several weeks of analysis, Microsoft stated that it found no direct correlation between the KB5063878 update and the reported SSD issues. According to the company, neither internal testing, telemetry, nor support feedback showed any increase in SSD failure rates or file corruption.

“We continue to monitor feedback following each Windows update and will investigate any new reports,” Microsoft said in a statement. The company also noted it had worked with several storage partners but had not been able to reproduce the issues described.

Phison: The Main Suspect, But No Proof

On the manufacturer side, Phison has been singled out, as its controllers are present in many of the affected SSD models. As a result, the company launched a series of tests on the SSDs mentioned in the reports.

After 4,500 hours of cumulative testing and more than 2,200 verification cycles, Phison has stated that it was unable to replicate the issues reported by users. No partners or professional clients have confirmed similar failures on their products.

In a statement, Phison suggested that some confusion may have been caused by misinformation circulating on social media. While the company has not observed any failures on its controllers, it remains cautious and recommends using heatsinks for SSDs that undergo intensive use.

Is This an Isolated Bug or a False Alarm?

At this point, it’s still hard to say. Both Microsoft and Phison have failed to identify a direct issue related to the KB5063878 update, despite weeks of investigation. Meanwhile, user reports do exist, but they remain rare and difficult to verify.

Until more concrete information comes to light, it’s advisable to avoid performing large file transfers on almost full disks if you’ve installed the August update. If you haven’t updated yet, you might want to temporarily suspend Windows Update until the situation is clearer.