Question: How do you find out if Guest Additions have been installed on your Linux guest running via Oracle VirtualBox on a Windows host?
Background We find this message to be ignorable when installing Guest Additions: "Could not find the X.org or XFree86 Window System, skipping."
Go into the Linux guest and run this command:
lsmod | grep -i vbox
You should see results related to vbox. If you see no results, then Guest Additions have not been installed.