I've just installed Debian Sid on my computer but I cannot mount external USB drives as you can see in the image.

enter image description here

Mounting failed
Cannot mount "SENZATITOLO"
Not authorized

What should I do?

  • an usb memory, but also with SD
    – Mitro
    Commented Mar 2, 2013 at 15:36
  • Either use sudo or set the users option for that device in /etc/fstab, so you can mount it as ordinary user.
    – ott--
    Commented Mar 2, 2013 at 18:17
  • 2
    @ott-- Probably not, I suspect OP is trying to use udisks to mount under /media. That should work...
    – derobert
    Commented Mar 2, 2013 at 18:50
  • 1
    What did you do to try mounting? Do you log in by typing your password in text mode or in graphics mode? Commented Mar 3, 2013 at 23:18
  • possible duplicate of Automount USB drives with no GUI requirement (halevt replacement)
    – jasonwryan
    Commented Mar 4, 2013 at 0:55

1 Answer 1


You are using a lightweight window manager. I've had this problem before in another such window manager. So it sounds like a problem with polkit to me. Does your system have a directory called /etc/polkit-1/localauthority/? If so, create a file (as root)... I use the nano text editor here. Paste into the terminal with CTRL + SHIFT + V.

su root
nano /etc/polkit-1/localauthority/50-local.d/55-storage.pkla

add the following lines:

[Storage Permissions]

now add yourself to the plugdev group:

usermod -a -G plugdev <your username>

logout and log back in. If it is polkit, you should be able to mount media now.

  • Some info on polkit or policykit, the sudo of systemd in debian. It is for mount/eject a removable media (CD/DVD, USB keys...) among others.
    – Timo
    Commented Oct 12, 2021 at 17:48
  • I got Not Authorized to perform operation and I used this and it worked, I added my user to the plugdev group. Did not have to logout.
    – Timo
    Commented Oct 12, 2021 at 18:02

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