Your Windows PC wakes itself up at 3 a.m. because Windows schedules its own maintenance then; one command names the culprit

The article was written for Windows 8, but the pieces it names are still in Windows. Desktops ship with “Allow scheduled maintenance to wake up my computer at the scheduled time” turned on, and the power plan’s “Allow wake timers” defaults to Enabled on AC power. When an app schedules a maintenance trigger, Windows sets a timer through the PC’s real-time clock, and the machine wakes in the dark.

Microsoft’s example is specific. From an administrator command prompt, powercfg /waketimers showed a timer set by services.exe, with the reason: “Windows will execute ‘NT TASK\Microsoft\Windows\TaskScheduler\Regular Maintenance’ scheduled task that requested waking the computer.” At the same time, Event ID 808 lands in the TaskScheduler Maintenance log, naming the task that asked for the wake. In Microsoft’s example it was Windows Update’s AUScheduledInstall.

Windows Update was “the first application to make use of the Regular Maintenance task scheduling feature,” and Microsoft notes the .NET Framework’s NGEN tool has also been seen scheduling it. As more software leans on overnight maintenance, a PC that sleeps through the night depends on knowing which of those requests you actually want.

The article never says whether the 3 AM default moved in Windows 10 or 11, and Microsoft hasn’t published a newer one that does.