It is possible to manually edit the Forefront TMG configuration, but it is only as a last resort short of rebuilding.The best advice is still to create and store regular backups.Another symptom you may notice is an empty Firewall policy screen.
An IT professional since 1996 Etienne has worked in various environments and is certified by Comptia, Dell and Microsoft.
Forefront TMG stores it configuration in an Active Directory Lightweight Directory Services (AD-LDS) database.
AD-LDS and its predecessor ADAM provides a directory very similar to Active Directory.
This database is a file located on the TMG server and there are also registry references to the directory.
From past experience it is usually a single entity that has become corrupt.