Microsoft suspects some PCs might not boot after Windows 11 January 2026 Update (KB5074109)

Microsoft is investigating reports of PCs failing to boot after installing the Windows 11 January 2026 Update (KB5074109). The issue may require manual recovery and affects specific PCs, with problems including a Black Screen of Death error and issues with Outlook Classic and File Explorer customization. The update also breaks sleep mode, Citrix Director, and Remote Desktop. Microsoft is collecting data on affected devices and has issued an emergency update to address the issues. If your PC is experiencing boot problems or other odd behavior after the update, manual recovery steps may be necessary.