I am using Xfce, and so the Thuner file manager. But I have a problem: When I plug in an external storage device (like my flash drive), I get the error in a diaglog box (shown in attachment). The only option I have is to manually mount is with the command line.

How to fix this?

Do you have the command "exo-mount" on your system?

Don't mount automagically here either, but that suits my tastes. I tried 'exo-mount -d /dev/sdb1' and get this

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 "Mount" error name "(unset)" destination "org.freedesktop.Hal").

'This sender' is a luser, not root. When I try that with a sudo in an xterm, all is well. But try it from Thunar with the perms for exo-mount at 4711, and GTK complains about running as root.

Methinks you'll have to drive a coach & four through your security policies. Read up on Hal, and you might do it neatly.

I hardly understand any of that.

Sorry.

I have the same setup and usb disks don't mount automatically. I don't consider that a problem.

You have to be able to mount them as a user before you can mount them as a user using xfce.

Either that, or change the security policies in gtk or hal, and on the system

How would you do that?

I guess it's OK to manually mount, but it would be convenient if Thunar would do it, or at least not bother me with that error when it can't.

Also, how can you make a normal user add/remove files from the mounted device?

It can be a bit tiresome. I simply use sudo mount <options>
Other things: Enter them in /etc/fstab and enter either
1. user, or users options - for details see man fstab
2. With vfat disks, you can specify uid and gid for your user and group. Then _you_ and not other users can write.
3. RTFM if you want to startt changing Hal.Google "hal site:freedesktop.org"