Why does my Windows go to sleep when plugged in?

My laptop is plugged in and when I go to sleep then whenever I wake up I find the laptop went to sleep too. It's quite unlikely to be power outages -- every night? beyond unlikely. Where could I check what's going on?

Solution 1:

It's sounds like it's going into hibernate.

1. Open up Power Options in the Control Panel. In Windows 10 you can get there from right clicking on the start menu and going to Power Options.
2. Click "change plan settings" next to your current power plan
3. Click "change advanced power settings"
4. Click the + sign next to "Sleep"
5. Click the + sign next to "Hibernate" and change setting to "Never"
6. Click OK

Additionally, you can check if hybrid sleep is enabled and disable that too.