I have only recently found the need to do a screenshot and have discovered it does not work.
How can I solve this?
Is this Kubuntu on a desktop ?
It’s on my Laptop, the one you helped me with, then I decided to install 16.04 instead of the kernel update.
I’ve discovered I am unable to do a screenshot!
What make/model laptop ?
Sorry, it’s ok now I fixed it.
There was no screen capture program installed!!! I’d have thought there would have been as it’s a new clean install of Kubuntu 16.04.
Mrs pooky has had enough of Window$10, with it being slow as a dead snail going backwards she wants me to install Kubuntu on it.
I’ll let you know if any screen capture program is or isn’t installed with a fresh install…
Just finished installing Kubuntu 16.04 on Mrs pookys laptop and alls well, spectacle was automatically installed along with the OS. So, I don’t know what I did with mine, probably somehow removed it without knowing!!!
Great stuff, glad you got it working 
sudo apt install spectacle
… then
Then I’m guessing in KDE it should “just work” because there’s already a keyboard shortcut for it.
Why do you ask ?
Or instead of using the terminal, you could do as I did and use one of the many package managers…