WakeWhile

WakeWhile prevents Windows from sleeping while a specific application is

genuinely doing work, and lets the PC sleep again once it goes quiet.

Unlike other keep-awake tools it is not a manual toggle, so there is nothing

to remember to switch off. You pick an app from a list of your open windows

and WakeWhile watches it, and every process it has spawned, measuring CPU,

disk, network and memory once a second. Each limit is an adjustable slider

with the live reading printed underneath it.

It is a single executable of about 90 KB written in C, with no installer, no

dependencies, no background service and no administrator rights. It writes a

plain text log recording which signal kept the machine awake, so the question

of why a PC will not sleep always has an answer you can read.