My wife needs to back up a few key files on her computer to external storage (NOT the cloud!) at fairly frequent intervals. I've been helping her with this, but we both know that it's not the best use of our time to do it that way. I've done the usual research and found sync'ing solutions as elaborate as GoodSync and as simple as SyncToy. I'm wondering is anyone has a suggestion for a simple, reliable sync app? Again, I'm not interested in cloud-based solutions (too vulnerable). I just want to sync to an external thumbdrive or hard drive... Any suggestions will be appreciated.