[Solved] Ubuntu digital clock (screensaver-like) cannot be dismissed

[jhann]

The digital clock comes up after some time of user inactivity.

But VirtualBox receives no keyboard inputs at this stage (even though the keyboard is indicated as captured), and the digital clock can never be dismissed.

VirtualBox 6.0.2. The only solution seems to be to initiate a Linux shutdown.

[socratis]

Do you mean the screensaver? If that's what you mean, I almost always (if not 100% of the time) disable all power savings modes and screen saver modes. There's no meaning on a host that's working to put the VM on a low-power state. Disable them.