Watching .iso files - freezes after approx 20min. HDD storage goes off

I just bought a WD TV LIVE and a 2TB WD My Book drive to hook into it.

I’m finding that after 20m in of viewing a .iso movie, the movie hangs.  If I exit back a screen to the menu, the arrow just keep spinning and spinning… and I notice the white light on the HDD is gone, like the device is powered down.

I force the power off on the WD TV LIVE, then unplug and replug the HDD in.

Then I boot the WD TV LIVE back up.

It takes about 2min to recognize the HDD, but then I can continue the .iso where I left off, and it will play for the rest of the movie.

I’m downloading some of the old firmwares, but is this a common problem, with perhaps a common fix?

What software was used to make the image (.iso) file? It may help someone help you as I seem to remember this was a concern at one time or another.