So it seems if you install Avid 8.4 on a windows 8.1 OR windows 10 computers title tool will not be able to save titles, it will just crash media composer (title tool will still run though), an uninstall and reinstall of 8.3.1 and the problem won't happen.
I've tested this on 2 seperate systems both Z800's one running windows 10 and the other windows 8.1.
(YES I know windows 10 is NOT supported but its what I had spare for a tille tool test)