GNOME3/Nautilus mount requires password

[Steve Dowe <sd@warpuniversal.co.uk>]

Hi,

I've Googled this aplenty and came across a multitude of possible
reasons why this is happening, but I would rather solicit an answer
detailing the "Debian way"...  I hope I've not missed this posted
elsewhere on the list/fora..

So, I'm running Wheezy, GNOME 3/gdm3, although my original install was
using LXDE/lxdm, and then XFCE/LightDM - all of which I like, but I keep
coming back to GNOME.

The problem is that I plug in a USB drive and cannot mount it with a
click in Nautilus without being prompted for my password.  I would like
to not be prompted for my password.

A few of the processes currently running on my system:

2515 ?        Ss     0:00 /usr/bin/dbus-daemon --system
6192 ?        S      0:00 /usr/bin/dbus-launch --exit-with-session
gnome-session
6196 ?        Ss     0:01 /usr/bin/dbus-daemon --fork --print-pid 5
--print-address 7 --session
2569 ?        Sl     0:00 /usr/lib/policykit-1/polkitd --no-debug

My user is a member of the sudo, plugdev & fuse system groups.  In
gnome-session-properties, PolicyKit Authentication Agent is ticked (it
points to
/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1, which
exists).

If I try to execute
/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1 on a
terminal, I get:

** (polkit-gnome-authentication-agent-1:10561): WARNING **: Unable to
register authentication agent:
GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: An authentication
agent already exists for the given subject
Cannot register authentication agent:
GDBus.Error:org.freedesktop.PolicyKit1.Error.Failed: An authentication
agent already exists for the given subject

When I try   "gvfs-mount -d /dev/sdb1"

I get prompted through the GUI to enter my password.  If I decline, I
get: Error mounting /dev/dm-3: Not Authorized

I get exactly the same if I try "udisks --mount /dev/sdb1" too.

I think I'm missing a pretty simple piece of the puzzle here.  I'm
guessing it's policykit somewhere.

A final point - the partition is encrypted with luks - but gnome-keyring
seems to do a good job of using my saved password to decrypt the
partition, when I click on the drive in Nautilus.  It's then the
password-less mount which fails...

If anyone could point me in the right direction, I'd be very grateful.

Many thanks,
Steve

-- 
Steve Dowe

Warp Universal 
http://warp2.me/sd