In connection with comments by jtonn and DD208. Curiously, I had the Power Nap (PN) enabled over the past couple of days without a suspicious reboot. However, I am yet unconvinced about the 'cure' for several reasons. One, of course, it is not a cure if a malfunction needs to be 'corrected' with a particular setting. Moreover PN enable may only obscure the Sleep Wake Failure (SWF), because this setting appears likely to keep the computer awake, therefore SWF not occurring.
This in itself is a whole new can of wrigglies. As I already mentioned in an earlier post, there seems to be a significant ambiguity and probably a serious omission in the correspondence between 'system sleep', 'disc sleep' and 'computer sleep'.
On top of that there is even less clarity about 'whatever sleep', 'standby' and 'hibernate' modes. This is where the situation with enable PN becomes uncertain. Before my enabling PN the iMac would go to 'sleep' mode from which it would 'wake' in two different ways:
- one, an almost instantaneous resume of where it was before 'sleeping', i.e. something akin to 'standby';
- the other, resuming from a state closer to what I'd call hibernation, where 'waking' involves the grayed screen with the 'running' bars before it allows back access.
It is my suspicion that SWF is somehow related to going into the standby or hibernate kind of state, which may be causing the failure, while remaining in a 'light' sleep, which is probably just suspension of disc and/or other activities would not cause SWF. Apparently, when PN is enabled there seem to be processes, which keep the system awake enough, not to get to where SWF occurs.
Something like that.
(Apologies for being overly verbose.)