Lot of reasons why an external HDD connection could be broken during a long period of access. I use them all the time and it's happened to me unavoidably despite my best efforts. We've all had a computer reboot on us for "no apparent reason." Frankly, this is one of my big fears of using encryption, that "something" goes wrong and data is lost forever.
Anyone remember a few years back one of the early big on-line backup companies went bankrupt? The bankruptcy manager gave customers 2 business days to get all their backed-up files off the on-line servers because the physical units were going to be seized, wiped and sold to satisfy creditors. Well, if you happened to be on vacation during those 2 business days you lost all your backed-up files permanently. And who you going to sue? A bankrupt Internet company?
File security is always a compromise between relying on yourself and relying on others.
When I see credit card processors having their servers hacked and millions of pieces of customer personal info wind up in the hands of hackers and criminals, I realize that self-reliance should come first. What about Sony's servers being hacked and it's discovered that account data was being stored without any encryption? We all remember that! LOL
