Windows 11 PC Wakes from Sleep Overnight Without Input

Windows 11 systems often use Modern Standby, also called S0 sleep, rather than the older S3 sleep state. Run `powercfg /a` to see which sleep modes are supported, and use `powercfg /sleepstudy` to inspect what happened during a sleep session. If S3 is available, switching to it may help, but changing the registry or firmware can cause problems on some systems, particularly laptops, so make a backup and verify hardware support first.

If you keep using Modern Standby, check `powercfg /requests` for applications, services, or drivers that are preventing normal sleep behavior. Specific requests can sometimes be overridden with `powercfg /requestsoverride`, but disabling updates or power-management components entirely is risky because it can leave Windows less secure.

Try disconnecting every USB device except the keyboard and mouse, then leave the computer asleep overnight. A failing device, dock, hub, or reconnecting peripheral can sometimes send a signal that the motherboard interprets as a power-button event. If the PC stays asleep, reconnect devices one at a time over the following nights to identify the culprit.

Because `powercfg /lastwake` reports the power button rather than a network adapter or scheduled task, this may be coming from the BIOS or motherboard instead of Windows. Check firmware settings for options such as Power Button Wake, Power On by PWR-BTN, Wake on Ring, USB wake, and other hardware wake features. Also look for an RTC alarm or scheduled power-on setting, especially since it happens at roughly the same time every night.