cdrom:unknown media/unsupported file
Submitted by Dr. David Alan Gilbert
I'm doing this in a nested KVM setup. So the host is an Fedora23 and that's got a Fedora 24 guest which has a CDROM device, and it's CDROM device still has the Fedora 24 install CD connected to it (Fedora-Everything-netinst-x86_64-24-20160409.n.0.iso).
Inside the happily running F24 guest, I'm running boxes and I click 'New'. It shows me: (CDROM icon) sr0 unknown media Enter URL -> Select a file ->
if I click the sr0 unknown media I get a little box at the top that says 'Unsupported file'
The CDROM is showing up in the file manager in my F24, and the perms on /dev/sr0 seems fine (e.g. od /dev/sr0 as myself dumps a load of octal).
It all works fine if I use an iso file in my home directory.