“Kernel driver not installed (rc=-1908)" on Mac Catalina 10.15

[DMC-163]

Starting the CentOS VM produces error “Kernel driver not installed (rc=-1908) on a Mac Catalina 10.15.4 OSX.
VirtualBox 6.1

Failed to open a session for the virtual machine CentOS-Template.

The virtual machine 'CentOS-Template' has terminated unexpectedly during startup with exit code 1 (0x1).

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: MachineWrap
Interface: IMachine {85632c68-b5bb-4316-a900-5eb28d3413df}

[multiOS]

In MacOS System Preferences > Security & Privacy > General check that the system is set to Allow apps downloaded from "App Store and identified developers" If not then unlock the screen with the system password, make the change then re-lock the preferences. See lower section of the screenshot below (Scroll down if necessary).

Keep that Preferences screen open and re-install VirtualBox. Watch the Preference screen for any prompt asking for permission to allow applications from Oracle. If a prompt appears then select "allow". If this prompt appears, it usually hangs around for about 30 minutes then disappears if no user action is taken.

Re-test VirtualBox (You might need to fully uninstall any existing VirtualBox installation if it doesn't work first time. I seem to remember having to do this a couple of times on new Macs before it worked fully).