http://blogs.technet.com/b/brookswhite/archive/2012/09/25/when-your-project-server-queue-slows-down.aspxI have a customer who has been fighting with slow/stopped queue processing every time they ran AD Sync, which is on a monthly basis. Running rebuild indexes on Draft and Published allowed the queue to start processing again, but this article from Brianen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)