This happens to mine if I have an update pending, worth checking if it's an intermittent issue.

I've dug into it several times. First it was network adapter, which for some reason had a default setting to wake on any received packet (lol, wut?). Then it was waking because there was some setting deep in the system about waking up for scheduled operations. (not scheduled tasks, but timers within individual processes... why???) Now it started again but this time the power management tools report no reason for the wake.

Do you have a Display port monitor, by any chance?

After adding one, I found out that when the display goes to sleep, Windows sees it as a disconnection, and 'helpfully' wakes up to reorganize all the windows onto one display. That wakes up the Display port monitor, which triggers another reorganization, and the cycle begins again.

So that's what it is. Got a TV connected via a D-port to HDMI adapter and the stupid machine wakes when I want to just turn off the TV after I put the PC to sleep.

Googling didn't get me too far obviously.

yes I do! I have noticed the sleep == disconnect thing. I'll look into it, thanks.

Serendipitous.

> Now it started again but this time the power management tools report no reason for the wake.

I ran into this after building a system and it was very frustrating. IIRC my problems were related to my network card and having virtualbox installed. Also turning off wake for my mouse helped (bumping the desk would turn on the computer).

An independently powered external HDD connected to your PC can also wake it up. I had this problem as well but haven't found a solution that doesn't stop me from using my current setup.

I had same issue, no reason for wakeups at all.

Wasn't any device, like network adapter and power diagnostics returned nothing.

Solution: reset motherboard NVRAM. No more mystery wakeups!

My screen keeps on coming back on rather than turning off. Got any leads on that?

Did you enable Windows Hello?