Mike, I am like you. I always keep an image of my OSes in case problems arise. But I realized it is not applicable with Win 10. After upgrading to 2nd build, I had all sorts of inexplicable problems and I kept looking for answers until I gave up and tried a clean installation of the 2nd build (I created the ISO myself). Then BAM! All problems are gone!
Different testers have different issues. So, if you guys are having some problems after upgrading to succeeding builds, the best solution is to do a clean install. It's really not fun, but that's just the way it is. Since MS keeps introducing new builds, backup images are useless for Win 10. It's not worth the time trying to find a fix to any Win 10 issues. Most of the time it's not...