Could you please tell us what you are doing with the clone tool -- the exact steps and settings -- that you are doing with the cloning tool. You also need to tell us exactly what happens (or doesn't happen) that seems wrong to you. Screen captures would be extremely helpful.
You could also watch this video:
I activate the cloning tool. choose a "dust spot" that I want removed.
Lightroom chooses a nearby and appropriate replacement, but nothing happens
after that. Should the repair be automatic, or should I be doing something
to move to the next step. None of my books etc. solve this problem. A
friend and regular user of Lightroom says I should uninstall and reinstall
Lightroom to see if that helps.
When the tool is activated there are two choices, clone or heal. Heal is more of a blending while the cloning should actually copy an area. The controls for the clone tool include an opacity setting. If the opacity setting is too low then it will appear as though nothing is happening. Could that be affecting you?
Thank you, thank you. Big help.