You can automatically logoff sessions after a specific idle time for all the users if a your administrator user
- Click to his username./hers username and click to User Management
- Click to User Sessions .
- Tick the Enable idle logoff box and set your max idle logoff time (minutes).
- Click Save
...
So if any user stays idle for > idle logoff time his CostOS will be closed.
Warning : this setting applies for every user.