i have been there god knows how many times, to find an empty shack, doesn't matter how many days i wait and i always go between 12am and 6am but, he is never there?! any help? oh and i have read the note on the wall.
The post maker said they had. Its possable but not mention anywhere it could be just to tell you the time to find him (no harm it reading it though just in case), now according to the wiki page he is actually always there the game just turns him off if you get close at the wrong time.
Wait in Raven Rock until about 11:30 then frun to the shack i think thats how i managed to finally get to him.
The note should be stuck to the wall of the shack by an arrow but it had fallen off for me and was on the floor, like any placed item it can be knocked around and with a strong spell or shout can possibly be blown though the floor and lost forever.