It sounds like it's not fitting your needs. For me I do a complete image backup then sync from that point on. That is, the image is to capture the machine as it is. Another app (I use GoldSync, SyncBack) syncs my files and only takes a hour or less depending on the changes.
Maybe you asked how to use their app. Sorry no, I won't use proprietary backup apps. Lesson learned long ago.
I have a 500 gig Maxell Genpro external drive. I have a 500 gig hard drive on my laptop which contains about 370 gigs of data. There wasn't much in the way of instructions included in the box other than saying click on Start. I plugged it in to the USB port to see if a menu would come up and I could set it up that way. It kicked off by itself. From what I read, it should take an hour to back up 10 gig of data. That seems rather slow to me but it proved to be accurate as it took 37 hours to back up the 370 gigs of data on my laptop. Since it is a laptop, I don't leave the Genpro plugged in to it all the time. I plug it in about once a week. Here is the problem. When I plug it in, it does another complete backup, or I guess it does because it takes about 36+ hours to run the backup. Common sense would make one think that only new data or data that was changed would get backed up. I doubt that on my busiest week would I change more than 10 gigs of data. Does anyone know if it is running correctly or how to make it only backup the changed/new data rather than the entire hard drive.
As always, thanks for your help and suggestions.