Most likely it's some AV program that's set to download new definition updates or something along those lines. As to why it's just now happening as opposed to not before... Who knows, but common reasons would be along the lines of registry cleaners removing an important value from the registry that controlled this behavior -- which would be pretty lucky if that's the full extent of the damage it did.
Hello,
So recently (within the past week) my computer (PC) has started waking up from hibernate or sleep within 7 minutes after I give it the command to do so.
I have not installed any new software before this started occurring, I have not added any new hardware, I have disabled all network adapters from being able to wake up the computer, and I have also used powercfg -lastwake and get the following:
Wake History Count - 1
Wake History [0]
Wake Source Count - 0
This means the computer doesn't show what the source is for waking it up. I also ran the devicequery command and have disabled all devices that were listed (mice, keyboards, etc) from being able to wake it up. Still no dice.
Interestingly, if I restart the computer and THEN sleep or hibernate, that works but is obviously not ideal (defeats the purpose of sleep or hibernate). So perhaps there is a process that is the culprit but I can't figure out how to identify which process that may be.
At this point, I am completely out of ideas and can't seem to find additional solutions online. If anyone has an idea, please let me know! This is so annoying and so strange that it happened seemingly out of the blue.

Chowhound
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