Windows 11 Security Update reportedly triggers SSD failures
SSDs reportedly fail following Windows 11’s KB5063878 update
A string of SSD failures has been reported following the release of update KB5063878 for Windows 11. This security update, according to multiple reports, can be triggered when large sequential writes are undertaken (50GB+). Following an error, Windows 11 fails to recognise affected drives, making them inaccessible. Similar symptoms have reportedly impacted HDD users as well.
According to @Necoru_cat, some SSDs are more susceptible to this bug than others. Phison-based SSDs have reportedly been “relatively prone” to this issue, though SSDs with various controller types are affected.
This issue has affected gamers due to the commonality of 50+ GB game downloads and large game updates. For now, this problem doesn’t appear to be widespread. However, there are enough reports of this issue to concern PC users. It is suspected that this update includes a regression that mishandles long sequential writes. This error appears to lock up SSDs, making drives disappear and become unrecognisable. This may cause data loss for users.
(Report from Necoru_cat on Twitter/X)
This Windows SSD failure state should be addressed soon with the release of a new hotfix. For now, Windows users should avoid long sequential writes. Gamers can update their games in sections, with pauses to prevent overly large sequential writes in a single instance. Alternatively, users can uninstall Microsoft’s KB5063878. However, this would leave users susceptible to the security issues that this update addresses.
You can join the discussion on Windows 11’s KB5063878 update reportedly causing SSD failures on the OC3D Forums.

