Problem scenario
You are using Oracle VirtualBox and a CentOS/RHEL/Fedora VM. You stepped away from your VM and now it appears the screen is locked. You do not see the desktop items you had open. You see there may be a new notification and you see the time. You tried to enter Ctrl-Alt-Del, Control-Alt-End, Control-Alt-Insert. None of the key combinations prompted you for your credentials. How do you log back in after the screen saver kicked in on your Red Hat distribution of Linux?
Solution
Click the mouse anywhere, then press Enter.