Windows 10 logs everything you do. You can view a list of every action that has been logged in the Event Viewer. Every event has its own ID and you can keep an eye on various events by creating custom logs in Event Viewer. The logs give you information about specific events which you can take, and use to find out other stuff like how long your system has been running. This will of course require you to filter the various event IDs for system boot, restart, and shut down. A simpler way to view Windows 10 up time is to use an app called TurnedOnTimesView.
Windows 10 up time
Download and run TurnedOnTimesView. The app has columns that list the date and time your system started, and shut down, the cause for the shut down, the shut down code, and other things.
You can scroll through the list and pick out any interval to see how long Windows 10 was running for that particular interval. You should know that by default the app counts Sleep as a shut down event. If you do not want Sleep to be treated as a Shut down event, go to Options>Advanced Options, and disable the Consider Sleep/Resume events as turn off/on option. You will find that doing so will greatly clean up the system logs you see.
In case your system was shut down due to an OS error, or something similar, you will see the reason for it in the Shutdown reason column.
This is pretty great way to tell when your system was shut down by Windows 10 to install updates. It’s also a reasonably good way to figure out what your active hours are. Windows 10 usually does a good job at figuring out when you don’t use your computer however, if you often get a prompt asking to install updates or restart your system while you’re working, you need to tell Windows 10 when your active hours are yourself instead of letting it guess and this app is a useful tool to help you do just that.
TurnedOnTimesView lets you check when you use your system, and when you put it to sleep so you can use it to figure out the best time to install updates. If the way the app displays information doesn’t work for you, you can always copy and paste it into a spreadsheet app of your choice. There’s also an option to export everything to an HTML file.
TurnedOnTimesView utilizes information that Windows 10 is already logging. It isn’t running any special scripts to keep track of your system activity.