I have used Glary's Utilities and CCleaner for the registry and have never had a problem, Glary's upon initial run on clients computers always shows hundreds of entries with missing links or pointing to wrong location, at any rate you click repair and in a few seconds it is done. When I reboot everything works OK, I don't know that it does any harm just leaving those entries or to remove them. I used one (test) IObit 360 and did have problems with some programs and had to reinstall those programs.