When I attempt to mount or unmount a USB drive is thwarted with following
error message:

"Unfortunately, the device system:/media/sdc1 (/dev/sdc1) named '1.0G
Removable Media' and currently mounted at /mnt/memory could not be
unmounted.
Unmounting failed due to the following error:
A security policy in place prevents this sender from sending this message to
this recipient, see message bus configuration file (rejected message had
interface "org.freedesktop.Hal.Device.Volume" member "Unmount" error
name "(unset)" destination "org.freedesktop.Hal")"

I have looked around for a config file but No Joy.