I’ve always been told that if you don’t know or recognize a certain registry in CCleaner then don’t delete it. Not everything that shows up means you should delete them. I do notice that sometimes if I delete certain registry keys associated with a program that sometimes they appear again in another registry class in the next scan. I look on it like a sort of chain reaction in that if you delete one key then it’s association will then no longer be relevant and so it comes up in the CCleaner scan in another area. I guess you have to keep deleting the keys of the programs until all association with them are gone. I hope this makes some sort of sense.
edit: Oh yes I notice on ccleaner I see an option to delete memory dumps. What I want to know is what exactly is a memory dump and is it safe to delete any?