Users of Lenovo laptops have reported technical issues following the installation of the Microsoft Windows 11 cumulative update KB5121003, released in August. The problems include random power outages and screen blackouts.
According to community reports, the affected devices incorrectly signal that the AC power adapter has been disconnected, causing the system to switch to battery power temporarily. Some users also experience complete screen blackouts.
Analysis suggests that the update modified several system drivers and components related to battery and power management, including battc.sys, CmBatt.sys, acpi.sys, CAD.sys, and pdc.sys. Conflicts within these updated components are suspected to be the cause.
One user conducted a 15-hour test after uninstalling the update, monitoring the AC power status every 50 milliseconds. During this period, no power loss or blackouts were recorded, confirming the update as the likely source of the malfunction.
