means killing other programs that may be using a shared dll or other file.
Indeed this could happen.
For instance, at Advanced level, Revo free listed all avast antivirus registry keys when I was uninstalling avast backup.
That's why, although I indeed use it, I don't recommend "cleaners" (not even CCleaner) for
general use. I use them for specific goals.
When I run Revo, I never let it delete automatically. I review exactly each item (files, folders and registry keys) and select exactly what *I* agree to be really related and dependant on the program being removed.
In the case, for example, of Avast with several different programs, I would review the results / suggestions of Revo and I would select only the items that I am completely sure I want and need to remove, leaving the other boxes unchecked.
In case I have any doubt, I don't delete the item, but I take note about it so to investigate it afterwards if necessary / wanted.