When rebooting, Windows displays a message indicating that Snagit has prevented Windows from shutting down.
This is a known issue with the Windows 10 Fall Creators Update.
Snagit 2018 and Later
This has been fixed in Snagit 2018.0.1 and later. To download the latest version, open the main Snagit capture window and click on Help > Check for updates.
Snagit 13 and earlier
As a workaround, turning off OneClick in Snagit will allow Windows to shut down properly. Follow the steps here to turn off OneClick.
If disabling OneClick does not fix the problem, please submit a support ticket with us.