Hey all, trying to see if anyone else has this issue and what I can do to fix it. My wife uses her 5K imac for wedding photography and she transfers huge amounts of data, 100gb at a time for some long weddings. So a lot of times she'll walk away or start a transfer before going to bed. Even at USB3, it takes a half hour or more. (Internal hybrid drive to external backup) But this morning (and a couple of other times now) shes woken the display to find the transfer has failed. Not exactly sure why, but the first time it happened, I changed a few settings. On Yosemite, I clicked the box that said 'Dont sleep when display turns off' or whatever it says. So theoretically it should stay on all the time, and realistically, it shouldn't matter as its Doing something, sleep should not be activated. Anything Im missing here, what can I do to keep it from doing this.