A significant security update rolled out by Microsoft with the Windows 11 24H2 (KB5063878) release is causing widespread issues for users, with reports surfacing that the update can render SSDs and HDDs inaccessible and may potentially corrupt user data.
Last week’s Patch Tuesday (August 2025) saw Microsoft release several critical security updates for Windows 10 (KB5063709 / KB5063877 / KB5063871 / KB5063889) and Windows 11 (KB5063878, KB5063875) systems.
Among them was a very important Defender update, intended to tackle the Lamma stealer malware found in new Windows ISO installations. However, as users and experts quickly discovered, the fix introduced unintended side effects for storage devices on Windows 11 24H2.
The issue began when users started experiencing installation failures with error code 0x80240069 on the KB5063878 update, but Microsoft’s subsequent hotfix seemed to alleviate those issues. Unfortunately, that did not mark the end of the saga.
According to a report highlighted by cybersecurity community members and corroborated by an X (formerly Twitter) user @Necoru_cat, the latest 24H2 update triggered critical failures with storage drives. Users report that after installing the update, SSDs and HDDs can disappear from the Windows environment, with SMART (Self-Monitoring, Analysis, and Reporting Technology) attributes becoming unreadable.
The issue seems to manifest most acutely during large sequential write operations. In one documented case, the problem became evident when updating a game (Cyberpunk 2077), causing the drive to vanish mid-transfer.
Once the drive disappears from the system, attempts to recover data are often unsuccessful, putting user files at significant risk.
This isn’t the first time a Windows update has caused problems for hardware performance, particularly among PC gamers and power users. Many affected users report the problem while gaming or updating large game files, where heavy drive activity is common.
The inability to access drives or the risk of data corruption can have severe consequences, particularly for users with critical work or irreplaceable data.
As of this writing, Microsoft has not issued an official fix for the storage drive disappearance issue. Users are advised to avoid installing the KB5063878 update if possible, especially if relying on large file transfers or critical SSD/HDD storage.
For those affected, unplugging the impacted drive and reconnecting it may temporarily restore visibility, but this is not an assured solution and may not prevent future data loss or corruption. Routine data backups and delaying installation of the problematic update are strongly recommended.
Bugs Following August Update
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