Just got a custom machine built, noted boot errors when the power has been re-applied after having been off for more than about 10 minutes. After shutting down properly, I then pull the plug for safeguards from lightning strikes on the power grid. I first thought the boot-up problem was related to known problems when external HDDs (2TB and a 3TB WD) are connected before start-up, which masked the power restoration issue. Got suspicious when I got the same problem with the external HDDs disconnected. Ran the same tests several times, got consistent results. I thought possibly the memory battery was weak, but I don't think so because the clock doesn't reset when the 120 volt power has been unplugged. My troubleshooting/diagnostic techniques are based on 40+ years of two-way radio repair, with having to learn computers "the hard way" over the last ten years or so. Sorry if I didn't mention more "numbers",
Brass-Monkey, would you please provide me additional information on this behavior, in order to find out the exact issue you are experiencing?
In addition to all those question, please let me know your system configuration to check compatibility