Windows 11 users who installed the August 2025 KB5063878 update have reported issues with SSDs disappearing from File Explorer and BIOS. Investigations suggest that the problem is linked to preliminary firmware versions of certain SSDs being inadvertently activated by the update. Phison technicians confirmed that the affected SSDs were running on this unfinished firmware, which was not intended for consumer use. Users are advised to update their firmware and back up data to prevent potential loss.