I've used many so-called system optimizers and have found many of them to include a registry cleaner and a registry defrag. There have been times after uninstalling a program that there are many references left behind by the program that are found by the registry scanner. Junk that I would like to see removed. It's more piece of mind knowing that I removed unwanted entries. I'm not being very savvy as far as what these entries can do if left behind. Can they trigger malware? Can they access a web site without my knowledge? I just feel better removing them. Of course a registry scanner won't get everthing.
My question, I guess, after removing many entries in a situation like the one above, is it useful to defrag the registry? I honestly don't see any performance improvements in the few system optimizers that I have used.
Any thoughts are appreciated,