My Windows 11 PC reliably wakes itself during the night after being left in sleep mode. I have already checked the usual causes, including network wake settings, magic packets, and software that might be powering the system on, but nothing has fixed it. Running `powercfg /lastwake` reports the wake source as a fixed feature: Power Button. The computer is untouched for several hours, yet it is powered on by morning. What else should I check to determine whether this is a BIOS, motherboard, hardware, or Windows sleep issue?
3 Answers
Try sleeping the PC overnight with every USB device disconnected except the keyboard and mouse. A failing device, USB reconnect, or unstable peripheral can sometimes be interpreted by the motherboard as a power-button signal. If the system stays asleep, reconnect devices one at a time on later nights to identify the culprit. Also check whether a BIOS update is available for the motherboard.
Since Windows is reporting the power button rather than a network device or scheduled task, this may be coming from the BIOS or motherboard instead of normal Windows wake settings. Look for BIOS options such as Power Button Wake, Power On by PWR Button, Wake on Ring, USB wake, RTC alarm, or other wake-related features. Disable anything you do not need, especially scheduled RTC wake events if the issue happens at roughly the same time every night.
Some newer systems use Modern Standby, also called S0 sleep, rather than traditional S3 sleep. You can check the supported sleep states with `powercfg /a`, and `powercfg /sleepstudy` may show what happened while the system was supposedly asleep. If the hardware supports it, switching to S3 sleep can help, although forcing S3 through the registry is not suitable for every system and may break cooling or other hardware-specific features. If you keep S0 sleep, `powercfg /requests` can help identify applications or drivers interfering with sleep, while wake permissions and Windows Update behavior should also be reviewed.
I had not considered that the power-button result could be a motherboard-level signal. I will check the BIOS alarm and USB wake options first, then test with the peripherals disconnected.