I did not do a clean install, I have many more programs than just FCS2 and did not think It was necessary to replace my engine when I was putting a new car stereo in. It would take me a week to do a clean install and some of my programs would be a pain to reinstall, my system is working just fine, no problems in anything yet, but I did clone my drive before I installed so if I do have a problem I’ll be ok. The only time I ever do a clean install is when I am having problems, why fix something that is working.