Although I've never been on this forum, I've been a user since the days of RegCleaner. One thing I've never done is change the suggested installation directory. Just a "me" thing I guess, but JV16 has never failed to load properly. I do delete earlier versions (folders), if they are present, but only after the newer version has installed and is running. Hope this helps.
I'm also going to add that I've used this registry cleaner on almost all of Windows versions, over the years, without problems (except for those pesky bugs which Macecraft is quick to fix). Currently I'm using JV16-X on an ASUS Win 8.1 desktop with all the bells and whistles. I also use it on an LG laptop with Win 7. There's also a Win 8.1 pad.