I'm on a Mac Pro desktop using Yosemite (10.10.5). I'm looking for a simple backup software that will do one thing: back up my entire hard drive and then update ONLY those files that I modify. It doesn't matter whether it updates them automatically (hourly or daily) or I would be required to do it manually (with the click of a button). I'm not interested in the multiple and constant backups that Time Machine does. I've tried using it--not for me. Any suggestions would be greatly appreciated.