heheheh ...
I wonder if it's as simple as somebody having a server or hard drive or router or whatever plugged into a switched outlet that goes off with the lights ...
I recall shooting a data system failure problem like that.
They'd had new flooring put in and when everything was put back together one tiny but vital piece of the corporate PBX and data system was wired to a switched circuit for the lights in an out of the way corner.
The failures only happened some time after everyone, including the cleaning crews, went home, and ALWAYS cleared when our repair folks got there - every damned time! /ubbthreads/images/graemlins/grin.gif (And it wouldn't fail when someone was waiting there for it TO fail.)
It was a timed remote-backup system for their data, so the failure only happened when that equipment cabinet was called upon to do the backup's in the middle of the night. (This equipment was a fiber-optic terminal and multiplexer, equivalent to 672 56K lines in bandwidth, with a minimal battery backup - about two hours.)
After a few times the guys figured out it was somehow tied in with the office lights, so we told the customer their stuff was just afraid of the dark, and to leave the lights on until we found the real problem - which we eventually did. /ubbthreads/images/graemlins/smile.gif
