Microsoft confirms Windows 11 KB5074109 January 2026 Update causes BSOD, boot issues on some PCs (commerical)

Microsoft has confirmed that the Windows 11 KB5074109 January 2026 Update is causing BSOD and boot issues on some commercial PCs. The company identified the root cause on non-consumer PCs and is actively investigating the issue. The problem arises from PCs that failed to install a previous security update and were left in an improper state. Microsoft has deployed a fix to prevent additional crashes, ensuring consumers won't encounter this specific issue for now.