I have inserted the the Guest Additions CD Image to Whonix-Gateway by pressing host+D, then I noticed the system respond and I try to open the folder where the CD image is, Whonix Gateway returns an error message:
An error occurred while accessing VBOXADDITION the system responded: The requested operation has failed:Error mounting: mount exited with exit code 1: helper faled with: mount: mount point /mnt/cdrom0 does not exist