Fresh installs 13.10 64-bit on one machine, and 13.04 on another, both behave the same:
Any insertion of a blank DVD-R disk results in message "unable to mount DVD-R location already mounted."
Attempted the suggestions above: Booted with blank DVD-R in drive, opened up Brasero, attempted to burn ISO image - Brasero still insisted that I needed to put a different DVD-R in the drive.
K3B reacts the same way when trying to burn a DVD. It will create an ISO image file just fine. libdvdread4 and libdvdcss are install, so is transcode, probably not relevant to this problem, but thought I'd mention it.
This was working perfectly fine in Lucid 10.04 for years, with the same batch of blank DVD-R disks, from the same cakebox, with the same hardware/dvd-drives.
So now, Ubuntu has no way of burning a DVD? Really?
Well, sure, it's not the end of the world, but what's the excuse? I'm now forced to run a Windows VM with other software that happily copies and burns all day long if I wanted it to.
Does anyone have a solution for this?