gksu: Gtk-WARNING **: cannot open display: :0

xorg sudo gtk gksu pkexec

221,495

Solution 1

If running Ubuntu 17.10 or newer, this issue can arise when an application has not been updated with full support for Wayland. As a workaround until the application is updated, you can run

xhost +SI:localuser:root

which will allow the root user to display applications on your desktop. Also see this Q&A for other possible workarounds: Why don't gksu/gksudo or launching a graphical application with sudo work with Wayland?

source

Solution 2

Try running xhost +localhost in your terminal, and then running the command again. This lets all users on your system (i.e. root) open windows on your screen. Make sure to use +localhost and not simply +, as it's more secure to allow connections from only localhost than from anywhere.

To make this permanent, edit the ~/.xinitrc file like this:

Run gedit ~/.xinitrc

Edit the file to look like this (it should be empty at the start):

#! /bin/bash
xhost +localhost &

Now save the file, log out and log in. Now everything should run just fine with sudo.

I can't reproduce your problem on 14.04, but this has worked for me in the past when sudo / gksu threw this error.

Sources:

Solution 3

Execute the following in your terminal:

nano /home/user/.bashrc # user = name of your user

Add the following line at the end.

export XAUTHORITY=$HOME/.Xauthority

Solution 4

xhost + fixed my problem

but Be aware that xhost + completely deactivates authentication and allows everyone to access all application on your screen...

xhost +si:localuser:root seems to work similar with proper authentication

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221,495

Author by

d_inevitable

Updated on September 18, 2022

Comments

d_inevitable over 1 year
All of the sudden gksu stopped working for me:
```
~$ gksu gparted

(gpartedbin:24252): Gtk-WARNING **: cannot open display: :0
```
The same happens with gparted-pkexec:
```
~$ gparted-pkexec 
No protocol specified

(gpartedbin:25454): Gtk-WARNING **: cannot open display: :0
```
What could possibly be causing this?

I am not running this through SSH or VNC. This is localhost in a normal terminal window.
- A.B. about 9 years
  
  You do not work in a graphical user interface or trying to run a program on a system (eg. via ssh) that no graphical interface provides.
- d_inevitable about 9 years
  
  @A.B. I should clarify that this is not via ssh. It's on local host in a very normal terminal window. Infact opening gparted from the application menu has the same result.
- d_inevitable about 9 years
  
  @muru when I run gparted without gksu I get Root privileges are required for running gparted.
- muru about 9 years
  
  Ok, try gparted-pkexec (without gksu) or gksu gpartedbin.
- d_inevitable about 9 years
  
  @muru both of them give me the same Gtk-Warning as above. Same for gksu gedit. I have already formatted my disk through the command line. So it is not specifically gparted that I am concerned about.
- TheSchwa about 9 years
  
  What is the output of echo "$DISPLAY" ?
- d_inevitable about 9 years
  
  @TheSchwa $DISPLAY is :0
d_inevitable about 9 years

This does work indeed. So does that mean its an access control restriction? Any ideas what the cause of this could be?
jalkoby about 9 years

Yes, it's a security feature of X. It allows only connections from your user to the xserver until told otherwise, I think. I'm not super sure why it's required for some apps and not others, and I don't have a clue why it would be doing it for gparted of all things. Perhaps you were tinkering and tightened security somewhere?
d_inevitable about 9 years

Well its happening with all apps, even gedit. Also I have noticed that it is only happening for one of my two users on the system, not the other. I've been tinkering with a lot of things, but not recently. A list of possible things that could cause this behaviour could help a lot.
jalkoby about 9 years

OK, not sure the cause, but I do have a fix. You need to add the xhost command to the .xinitrc file for the user so it runs when you start the session.
reexmonkey over 7 years

Thanks it worked! Desperate was I but you saved my day!!!
Steven Roose over 7 years

This did not work for me... Any other idea?
IgorGanapolsky over 7 years

This yields an error: xhost: unable to open display ""
rmin over 6 years

On redis, it was suggested to use xhost +local:. After that I was able to launch gparted from the terminal, but using xhost +localhost didn't work.
lobner over 6 years

Indeed! xhost +local: fixed mine! It yields non-network local connections being added to access control list which is what is needed.
Cutton Eye over 6 years

@MDMower Thx for editing, learned something new =)!
Cutton Eye about 6 years

@pomsky Thx for adding the link ;)!
Cutton Eye about 6 years

In 18.04 X-Org will be used again as default. So this problem should vanis then. see
Nathan B about 6 years

I get xhost: unable to open display ""
Amit Kumawat over 5 years

Would be useful if you could add some explanation of how this solves the problem, and whether it has any adverse side effects?
Mecanik over 3 years

Same problem occurred with Ubuntu 20 and this solved it.