Although I had set my Surface Pro 3 to Sleep when I closed the lid, I found that whenever I opened the lid and pressed lightly on the Power button, all the open windows and programs would be shut down. I was thinking – did a resume from Sleep closed all programs? Since that seemed impossible, the only other cause could be that when I put the Surface to Sleep, either by closing the lid or by clicking on Sleep button, it would instead end up shutting down!
Surface shuts down when I close lid or click on Sleep
Surface Pro 3 runs Windows 8.1, so basically the process to troubleshoot this issue would be similar as, for any other Windows 8.1 laptop.
The way Surface works is that if you if you don’t use it for a few minutes, the screen turns off and Surface Pro 3 goes into InstantGo power state, which can resume it very quickly. If you don’t use Surface Pro 3 for several hours, it will enter Hibernation state.
InstantGo in Windows 8.1, replaces the Connected Standby of Windows 8. It maintains network connectivity when the screen is turned off, and it permits the system to update things in the background, and resume its job whenever required. All this is done primarily to save battery power
So in effect, what it would mean, that when your Surface enters Hibernate, it subsequently shuts down.
Here are few troubleshooting steps you may want to try, if your Windows 8.1 laptop or Surface Pro 3 shuts down when you click on Sleep:
1] Ensure that all your device drivers are up-to-date.
2] If you are using a Custom Power Plan, delete it and use one of the built-in standard Power Plan and see if the problem goes away. Restore default settings for that plan and see if it helps. Else change the power plan and see if that helps.
3] Run the Power Troubleshooter. It will detect your system settings that can affect power usage, such as timeout and sleep settings, display settings, and screensavers, and restore them to their default settings.
4] Open Control Panel > Power Options > System Settings, and uncheck Turn on fast start up. This worked in my case.
5] Read this post Hibernate shuts down computer running Windows 8.1 and see if something there helps you.
If you need additional help, this post on how to troubleshoot Power Plans with PowerCFG Tool may guide you.