Every seen a problem with the AD LDS database file get so big that it filled the hard drive of your TMG firewalls? If not, now you can say that I know somebody that had this problem!
Check out what might cause this problem over on the TMG firewall team blog at:
http://blogs.technet.com/b/isablog/archive/2013/12/11/the-case-of-the-big-ad-lds-database.aspx
HTH,
Deb