A recent KBTV video discusses Isolation Modes in VMware ThinApp. Isolation modes allow you to control the degree to which a virtualized application can read from and write to the local, physical PC where the virtual application resides.
ThinApp automatically configures isolation modes for directories in the file system and for registry subtrees in a ThinApp project. You can change the default isolation modes. Our video includes an overview the theory of isolation modes and how to implement them in practice.