Why the Windows 11 KB5063878 Update Can Crash Your SSD – Risks and Fixes

In mid‑August, Microsoft released the KB5063878 update (internal version 26100.4946) for Windows 11 24H2 users, primarily to fix security problems while adding new features.

However, many users reported a severe bug: the update could cause solid‑state drives (SSD) and mechanical hard drives (HDD) to fail, leading to "disk drop" where the drive becomes unrecognizable by the system.

The issue also affects Windows 11 23H2 and Windows 10 users. Affected Windows 10 update IDs include KB5063709, KB5063877, KB5063871, and KB5063889; Windows 11 update IDs include KB5063878 and KB5063875.

The problem was first discovered by an external user, @Necoru_cat, who noticed that after installing KB5063878, the SSD used for the game Cyberpunk 2077 became invisible during patch installation.

Further testing showed that writing more than 50 GB of data continuously, with SSD controller utilization over 60 %, triggers the failure, and SMART information becomes unreadable. Even after a reboot the drive may temporarily reappear, but subsequent writes cause the issue again, risking data corruption.

The bug appears more likely on SSDs using Phison controllers without DRAM cache, such as certain models from Corsair, Kioxia, Fikwot, and others listed below.

Corsair Force MP600

Phison PS5012‑E12 series SSDs

Kioxia EXCERIA PLUS G4

Fikwot FN955

Samsung 970 EVO Plus (example)

InnoGrit‑based SSDs

Maxio SSDs

Kioxia M.2 SSDs

@Necoru_cat tested multiple SSD brands using the data‑intensive game Cyberpunk 2077 and identified two failure levels: NG Lv.1 – the SSD disappears during write but returns after reboot; NG Lv.2 – the SSD remains undetectable even after reboot, effectively bricking the drive (e.g., Western Digital SA510).

The issue has not been globally confirmed; only a limited number of users have reproduced it, and neither Microsoft nor SSD manufacturers have responded.

Users planning extensive data writes are advised to uninstall KB5063878 (and related patches) via Settings → Windows Update → Update History → Uninstall Updates, then restart.

Regardless of the update, regular backups are essential. Follow the 3‑2‑1 backup rule: keep three copies of data on two different media, with one copy stored off‑site.

Ironically, KB5063878 was itself released to fix earlier critical bugs, illustrating the "bug‑fix‑bug" cycle that can occur in large software projects.