Ubuntu 14.04 print screen button does not work

My PRTSC button also didn't work for a brief moment, and I haven't figured out what caused it, as after reboot it started working again; however what i can offer is a workaround - you could set an alternative shortcut to taking screenshot

The default program to take screenshots in Ubuntu is, as you may now, gnome-screenshot . You could open System Settings -> Keyboard -> Shortcuts, and under custom shortcuts press plus button.

A menu such as bellow will appear, where you can enter description and actual command to run.

In the name field enter the description. In the Command field, well, enter the command. In my example, I've linked gnome-screenshot -w, which is "take screenshot of current window". For more information on gnome-screenshot options, refer to man page (man gnome-terminal).

Now after you have entered name and command, press apply, and you will see this custom shortcut be added to your list. Click on the "Disabled", and the text should change to "New accellerator". This is where you set a new shortcut, for instance Super+Shift+P.

Among other things, you could try resetting settings for keyboard to default as shown in this post, but I believe it's a bit to extreme step for such simple problem.

I've also found that for some folks changing kernel.sysrq in /etc/sysctl.d/10-magic-sysrq.conf helped, but I believe it to be unrelated; with PRTSC button inactive and active, that value was the same , 176.

If the print button randomly stops working, please ensure that the previous print screen dialog box is actually closed first. The print button will not work until then(seems apparent but can happen if you are jumping back in forth between applications a lot).