Just a SWAG, but I don't think my hard drive has enough space to handle a restore to where it was in late September unless I delete most of what I've added since then (and wouldn't deleting those things make it harder to retrieve the old stuff?).   I'm really not terribly savvy about these things. But when I accidentally deleted half of the Singtime Frolics concert I had recorded, in the process of learning how to use iMovie, I checked into the question of whether I could retrieve those video files. Basically, the tech people I talked to seemed to think it would require a lot of tech service time and still might not work.   (I think they told me then that the best bet was to keep as much space open on my hard drive as possible -- in other words, don't use your computer much, and especially don't save many files, until you've retrieved the old stuff.)