Looks like this has happened before with no solution, but I'm checking just in case because it is a game breaker (can't complete the unmoored world evacuations if you don't finish Doireann's nutriabh quest). Doireann and I were about ready to go to Battahl (she already had made the nutriabh) when I accepted an accursed escort quest from her father (what the hell was I thinking?). When I finished the escort quest and returned to Sacred Arbor, Doireann was not there. There was a quest marker where she usually hangs out, but she was not there, nor was she anywhere in Sacred Arbor. I waited over a week. I logged out and back in. I went to both morgues -- she is not there so SHE IS NOT DEAD. I checked with Sarah back in Battahl and she noted that she was expecting me "anon" with the elf and the nutriabh. I've used almost all my wakestones travelling around looking for Doireann. She is simply gone from the game. I hate those damn escort quests anyway, but this one has ruined my play-through -- unless someone has discovered some kind of fix. Hate to quit and start a new game (this character is level 50, so I've played quite a bit), but that seems preferable to going all the way to the end of the game before I can even start working on a clean play-through.