My sister has 1 toon she hasn't been able to use the Quest Module on since he dinged 100 2 weeks ago.
No error message at all just locks the game up completely... Not her computer, just the game so she can window out & then rt-click close the WoW window. rather than having to do a reboot.
So far I have (not all done in the order written) deleted Cache files, round filed the WTF & Interface folders, repaired the game, uninstalled the game as well as Curse & ALL of the addons, deleted the saved variables. reinstalled & enabled each add-on individually starting with Carbonite & the only time the Worgen Hunter is locked & unplayable is with Carbonite Quest enabled.
There is no a single setting that I can find that would account for this.
I was trying to find a command line or button to reset the Blizzard UI on just this toon but not finding it & the GM's seem to be useless & keep telling her the same steps that haven't worked the last 50x.
I really believe this is a Blizzard mess but they aren't dealing with it & she lives across the hall
Edit: I do keep up with the latest version from Github