Migrated from:
https://github.com/Whonix/Whonix/issues/168
Known issue with workaround:
https://www.whonix.org/wiki/Known_Issues#Mounting_.28CD.2FDVD.29_Devices
Should still be fixed for better usability.
Asked on mailing list:
http://lists-archives.com/kde/15416-device-auto-mounter-can-not-mount-the-following-device.html