If your Kali desktop turned completely black after deleting the default wallpaper, or not changing wallpaper and you’re getting errors like:
Failed to load image file ‘(null)’: Error opening file /usr/share/backgrounds/kali-16x9/default: No such file or directory
It’s because XFCE was still trying to load the missing default wallpaper.
Real Fix (Tested & Working on Pi 4)
Choose any image you want to use as wallpaper.
Rename it exactly to: default (with no extension like .jpg)
Move it to this folder:
sudo mv default /usr/share/backgrounds/kali-16x9/
Then reboot your system:
reboot
Boom! The wallpaper is back, and the black screen issue is gone.
i got this idea while bathing hahahahah and it worked man I was so frustrated trying for 2hours but issue was so simple