I'm going to ask a friend that's a whole lot smarter than I am to give this a look so I want to make a few observations.
(a) I get this in Ubuntu running Unity, Ubuntu GNOME running either GNOME Shell or GNOME Classic, and the Flashback sessions whether installed in Ubuntu or Ubuntu GNOME. (b) I've had no problem with Brasero creating data discs or burning iso images so I think any problem with Brasero is not particularly related to this bug. (c) I just performed a fresh install of Ubuntu Trusty using the 20140701 i386 daily image, fully updated it, and inserted a blank DVD which did reproduce this bug, but you can see from the attached screenshot that 'gnome-settings-daemon' is NOT installed in a default Ubuntu installation so this is either NOT a 'gnome-settings-daemon' bug or it also effects 'unity-settings-daemon'. ** Attachment added: "Screenshot from 2014-07-03 00:07:34.png" https://bugs.launchpad.net/ubuntu/+source/gnome-settings-daemon/+bug/1069964/+attachment/4144349/+files/Screenshot%20from%202014-07-03%2000%3A07%3A34.png -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-settings-daemon in Ubuntu. https://bugs.launchpad.net/bugs/1069964 Title: Unable to mount Blank CD-R disc. Location is already mounted. Status in “gnome-settings-daemon” package in Ubuntu: Confirmed Bug description: This error message comes up, while still able to burn, read/write etc. It occurs in quantal when inserting a CD/DVD into the drive, but it did not happen in precice. Screenshot: http://i47.tinypic.com/4v0aj6.png Burner: LG HL-DT-ST DVDRAM GH24NS90 ProblemType: Bug DistroRelease: Ubuntu 12.10 Package: gnome-settings-daemon 3.4.2-0ubuntu14 ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5 Uname: Linux 3.5.0-17-generic x86_64 NonfreeKernelModules: fglrx ApportVersion: 2.6.1-0ubuntu3 Architecture: amd64 Date: Mon Oct 22 19:50:35 2012 ExecutablePath: /usr/lib/gnome-settings-daemon/gnome-fallback-mount-helper InstallationMedia: Ubuntu 12.10 "Quantal Quetzal" - Release amd64 (20121017.5) ProcEnviron: LANGUAGE=en_GB:en PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_GB.UTF-8 SHELL=/bin/bash SourcePackage: gnome-settings-daemon UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-settings-daemon/+bug/1069964/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp