Sstrhsrtj

I typed apt-get upgrade in terminal, and after that the sound is disabled, and I can't control screen brightness anymore.
And it's only on root account. The sound is enabled on other accounts.

I'm running Kali Linux 64 bit version 2016.2.

from kali linux official issue page :

Those issues are due to GNOME being in transition between GNOME 3.20 and GNOME 3.21 in Debian Testing currently. We have to wait until updated mutter/gnome-shell enter Debian Testing (and thus Kali Rolling).

but you can use xbacklight to change brightness from the command line, to install it open your terminal and type :

sudo apt-get install xbacklight

then type xbacklight -set 30 to change your brightness to 30% for example.

Intermediary Solution to Problem:

1. 
   

   Open leafpad or gedit and save to desktop with the name:

   
   
   

   Brightness Control.desktop

   
   


2. 
   

   Right click the newly created file (Brightness Control.desktop), select Properties, and paste the following under Basic tab in the Command: section:

   
   
   

   sudo -H gedit /sys/class/backlight/intel_backlight/brightness
   
   

   
   



3. Select Permissions tab and check Allow executing file as program box.



4. 
   

   Execute the file by clicking on it and change the number value. Ensure you do not select a value too low (screen will black out) or too high (will not save). To check your maximum screen brightness value type the following in terminal:

   
   
   

   cat /sys/class/backlight/intel_backlight/max_brightness
   
   

   
   
   

   Note: You may need to verify that the intel_backlight directory exists as it may be different if your system is not using Intel graphics. Just replace the directory location by navigating through area to determine vendor/directory.