Board Thread:Off Topic/@comment-119.94.4.227-20150414105747/@comment-6881629-20150414111341

Karliah just leaving (and generally not working right) is on the Trinity Restored bugs list here if she's already left and you have no past save to reload theres nothing you can really do i'm afraid, unless your on the PC then you can try bring her back and reseting her ai and/or try progressing the quest with console commands.