This happens pretty much on every Windows 10 update. Last time I wrote about it was for Windows 10 Fall Creators Update (1709). The blog post is here.
Yes, again this absolutely ridiculous waking up begun. None of my previous fixes/hacks/duct tape/bubble gum patches worked. For weeks I either shut down my PC or just suffered on random power-ups.
When your Windows pops up from sleep, there is one very simple command to figure out why it happened. This is something that has worked for years in multiple Windows-versions: powercfg.exe /waketimers
(btw. you need to run that with Administrator permissions, regular user won't cut it.)
The result in each case was something I didn't expect to see:
Timer set by [PROCESS] \Device\HarddiskVolume6\Windows\SystemApps\Microsoft.Windows.StartMenuExperienceHost_cw5n1h2txyewy\StartMenuExperienceHost.exe expires at on .
What the hell is StartMenuExperienceHost.exe and why would I need it for anything? I have no clue. Also, why would I need that unknown piece of crap so badly it can wake my computer up? Again, no clue. Honestly, I would delete the darned file if it wasn't part of Windows system. Given the protected status of system files I really cannot rip the junk off. Unfortunately.
This harrasment kept going on for weeks as I was researching for a solution. Most of the suggested fixes are about Troubleshooter, Power or disabling Wake Timers or Automatic Maintenance's option Allow the scheduled maintenance to wake up the device at the set time. Neither of those really help.
Finally I cracked it! While looking for things to try, I stumbled into Microsoft community discussion System keeps waking. ShellExperienceHost.exe. Build 17074. There one of the suggestions was to check the Local Group Policy. There is Computer Configuration > Administrative Templates > Windows Components > Windows Updates > Enabling Windows Update Power Management to automatically wake up the system to install scheduled updates. Setting it to Disabled makes the difference!
I have to agree with a comment in Reddit:
Microsoft needs to provide a simple, global switch to NEVER EVER under any circumstances wake the PC up from sleep/hibernation as if the PC was shutdown and unplugged from the wall.
Its really puzzling to try and understand why such an option doesn't exist.