Ubuntu – Automount when clicking on disks in GUI file manager suddenly stopped working in Ubuntu. (“Unable to mount…Not authorized to perform operation.”)


I'm using Ubuntu 18.04 with nemo as the file manager, and out of nowhere I can no longer mount disks or partitions which show up just by double-clicking them, when just a few weeks ago this worked perfectly fine! Any idea what changed? Perhaps an update messed it up?

The error is:

Unable to mount NAME_OF_DISK. Not authorized to perform operation.

Screenshot from nemo file manager:

enter image description here

This answer doesn't seem to help me either, as I just booted up and have nothing open really. Repeated reboots don't solve the problem. How would I find out which application might be holding the lock? Mount Flashdrive: Not Authorized to perform operation.

Note that the work-around is to manually do it with sudo, but I really don't like having to use sudo! Ex:

sudo mkdir /media/mydisk
sudo mount /dev/sdb1 /media/mydisk

Or this works too:

sudo gnome-disks

Then use the gnome "Disks" utility to mount via the GUI.

If I do this though I cannot view the mounted partition unless I also run my file manager as root. Ex:

sudo nemo

Then navigate around in a GUI file manage window with elevated permissions.



  1. https://superuser.com/questions/1151993/usb-automount-fail-not-authorized–related to Polkit and plugdev group?

Best Answer

Solved. For my particular case the problem was Chrome Remote Desktop. Uninstalling it solved it.

sudo apt autoremove chrome-remote-desktop 

Source for the uninstall command was JVApen here.

I've had many problems with Chrome Remote Desktop on Ubuntu, so I'm not really sure what to do about it. For now I suppose I'll leave it uninstalled and try using NoMachine instead, although that requires messing with your router settings and opening up port-forwarding from the outside internet to your internal local area network, which Chrome Remote Desktop seems to avoid by (I'm guessing) instead using a reverse tunnel through an outgoing connection from your house out to a Google server. In other words, the Google approach is probably safer, and is certainly much more convenient, if only it worked. [UPDATE: I'm sticking with NoMachine. Here's some configuration settings I wrote down that you may find useful.]

Note that I originally installed Chrome Remote Desktop using these instructions here:

  1. https://medium.com/@vsimon/how-to-install-chrome-remote-desktop-on-ubuntu-18-04-52d99980d83e and here:
  2. https://superuser.com/questions/778028/configuring-chrome-remote-desktop-with-ubuntu-gnome-14-04/850359#850359.

I then had this problem here:

  1. Can't connect to Chrome Remote Desktop on Ubuntu 18.

I've also had problems with Chrome Remote Desktop taking over audio, and making my audio not play back, and other things like that. Google's support for it on Linux is somewhat poor, and I'm continually fighting with it it turns out.


  1. Mount Flashdrive: Not Authorized to perform operation
  2. https://medium.com/@vsimon/how-to-install-chrome-remote-desktop-on-ubuntu-18-04-52d99980d83e
  3. https://superuser.com/questions/778028/configuring-chrome-remote-desktop-with-ubuntu-gnome-14-04/850359#850359
  4. "Some required components are missing"--cannot connect from Linux to Windows w/Chrome Remote Desktop
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