About Modern Macs Not Waking after Hours of Sleep (Hibernates/Powers Off) (again)
I still see posts in Apple's forums about this behavior on later Macs, including desktop models on AC power. I don't own a new Mac Pro but recently saw a post that sounded like it was the same issue ('feature'). Rather than repeating all the notes/PMset info again, here's a link to my post in Feb 2013 on Why 2012 iMac/Mac Mini Hibernates/Powers Off after Hours of Sleep even with Hibernate disabled. Includes some PMset changes that may or may not help. (It did back then, but I've not retested after upgrading to Mavericks. Also has notes about sleepimage file reappearing.)
(Update - reader mail in reply to above/previous tip I'd used earlier.)
"Re: About Modern Macs Not Waking after Hours of Sleep
No idea why, but I've now seen at least 2 cases where "sudo pmset autopoweroff 1" and "sudo pmset standby 1" worked but "sudo pmset autopoweroff 0" & "sudo pmset standby 0" didn't!?
(What mac models and OS X version were those 2 using?)
Agreed that does seem odd (opposite of expected setting), but if any readers find that helps (where 0/disabling didn't), let me know.