Shutter:FAQ

Computer is awake after a hibernation or sleep action

When you execute a hibernation or sleep action in Shutter, you might find your computer woken up later or not even entering a suspended mode.

First, check that the Shutter's action status says "Finished", rather then "Error" or similar. This will tell whether Shutter was able to successfully initiate a suspended mode (e.g. sleep, hibernation, standby). However, despite a successfully initiated suspended mode, there are several things which can interfere with the process of entering a suspended mode, for example:

1. Other applications and services can prevent the system from entering the suspended state by cancelling it before it completes.
2. The system can be awoken from the suspended state by hardware and software events, e.g. keyboard/mouse activity, wakeup timers, Windows Update.

When these circumstances occur they occur outside of Shutter's control, but you should be able to prevent both of these circumstances, and here is a list of things to try:

1. Enable the "Disable wake event" option in Shutter's action, and then check if the system continues to exhibit the same symptoms.
2. Disable the "Allow wake timers" option in Windows Power Options, and then check if the system continues to exhibit the same symptoms.
3. Find out what causes the system to be reactivated (woken up) from the suspended state by examining the logs via Event Viewer » Windows Logs » System. Look out for power related sources, e.g. "Kernel-Power", "Kernel-Boot", "Power-Troubleshooter".
4. One of the most common offenders is a Windows Update procedure that wakes up your computer to check and install updates. Unfortunately, it may not put your computer back into the suspended state afterwards. You can disable the ability of this task to wake up your computer by modifying the UpdateOrchestrator task in the Task Scheduler.

See also this comprehensive list of ways to prevent Windows 10 from waking up your computer:
https://superuser.com/questions/973009/conclusively-stop-wake-timers-from-waking-windows-10-desktop