I just had the most amazing experience. My main drive got tremendously
messed up (due to Microsoft, no less), so after trying to salvage things
for about 5 hours, mostly spent in remote sessions with Microsoft support,
I decided to go back to my externally duplicated drive (see earlier posts).
I was reluctant to do that right away, because the duplication was done on
May 27, 10 days ago, and I didn't relish the thought of querying my backups
for only the files changed/created after the cloning date. Something was
sure to go wrong in that process.
But I steeled myself, swapped in the clone from May 27 and fired up the
computer. To my amazement, the files from May 27 - today were on the
computer! And yet, the messed system and program software was back to its
proper state. How could this be? Either there is a God after all, or
somehow Dropbox is set up to automatically (and really swiftly) bring me up
to date regarding the files in one's Dropbox folder (which in my case are
virtually all my data files).
So the combination of drive-duplicating (using an external box) and Dropbox
is much more helpful than either alone.
I did get Shadow Protect (trial), but have not set it up yet, because it's
not obvious how to do that.