In my case, I was able to fix the issue without removing lightdm - I discovered, that for some reason (I never made according changes, I am 100% sure)
/etc/lightdm/lightdm.conf contained [SeatDefaults] greeter-session=unity-greeter user-session=ubuntu autologin-user=<my_user> I commented out the last line in #autologin-user=<my_user> and that solved the issue with the missing rights for me. Nota bene: Autologin was NOT active - I had to login with password, and I NEVER selected to autologin as we have a multi-user desktop here at home. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/851055 Title: [Oneiric] 'Not Authorized' error given when mounting device Status in “lightdm” package in Ubuntu: Fix Released Status in “lightdm” source package in Oneiric: Fix Released Bug description: Oneiric Ocelot with latest update. Nautilus, Disk Utility are unable to mount/format/create partitions on USB drives. User is presented with 'Not Authorized' error. ProblemType: Bug DistroRelease: Ubuntu 11.10 Package: gvfs 1.9.5-0ubuntu1 ProcVersionSignature: Ubuntu 3.0.0-11.18-generic 3.0.4 Uname: Linux 3.0.0-11-generic x86_64 ApportVersion: 1.23-0ubuntu1 Architecture: amd64 Date: Thu Sep 15 18:07:58 2011 EcryptfsInUse: Yes HotplugNewDevices: /dev/sdb /dev/sdb1 /dev/sdb3 /dev/sdb2 HotplugNewMounts: InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Beta amd64 (20110901) SourcePackage: gvfs Symptom: storage Title: Does not detect hotplugged storage device UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/851055/+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