OK, it is this issue. PolicyKit is choking udisk2. Here are the sample commands:
$ udisksctl mount -b /dev/sdm1 --no-user-interaction Error mounting /dev/sdm1: GDBus.Error:org.freedesktop.UDisks2.Error.NotAuthorizedCanObtain: Not authorized to perform operation $ udisksctl mount -b /dev/sdm1 ==== AUTHENTICATING FOR org.freedesktop.udisks2.filesystem-mount === Authentication is required to mount 0c76 TS512MJFLASHA (/dev/sdm1) Multiple identities can be used for authentication: 1. Administrator (administrator) 2. User1 (user1) Choose identity to authenticate as (1-2): 2 Password: ==== AUTHENTICATION COMPLETE === Mounted /dev/sdm1 at /media/user1/USB512MB. Since the " --no-user-interaction" command fails, users can't mount external devices without selecting a sudo user and password authenticatation. Once it's mounted, I can unmount normally. The file /var/lib/polkit-1/localauthority/10-vendor.d/com.ubuntu.desktop.pkla contains (partial): [Mounting, checking, etc. of internal drives] Identity=unix-group:admin;unix-group:sudo Action=org.freedesktop.udisks.filesystem-*;org.freedesktop.udisks.drive-ata-smart*;org.freedesktop.udisks2.filesystem-mount-system;org.freedesktop.udisks2.encrypted-unlock-system;org.freedesktop.udisks2.filesystem-fstab; ResultActive=yes We need something for the little guy to mount the external devices. Maybe a rule in /usr/share/polkit-1/rules.d/ because System Settings->Removable Devices "ain't git'in 'er done." -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1240336 Title: Not authorized to perform operation / Unable to determine the session we are in: No session for pid To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm/+bug/1240336/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs