ThinApp User’s Guide : Capturing Applications : Capturing Applications with the Setup Capture Wizard : Defining Isolation Modes for the Physical File System

Defining Isolation Modes for the Physical File System
Isolation modes determine the level of read and write access to the native file system outside of the virtual environment. You might adjust isolation mode settings depending on the application and the requirements to protect the physical system from changes.
The selection of isolation modes in the capture process determines the value of the DirectoryIsolationMode parameter in the Package.ini file. This parameter controls the default isolation mode for the files created by the virtual application except when you specify a different isolation mode in the ##Attributes.ini file for an individual directory.
The selection of a directory isolation mode does not affect the following areas:
ThinApp treats write operations to network drives according to the SandboxNetworkDrives parameter in the Package.ini file. This parameter has a default value that directs write operations to the physical drive. ThinApp treats write operations to removable disks according to the SandboxRemovableDisk parameter in the Package.ini file. This parameter has a default value that directs write operations to the physical drive.
If you save documents to the desktop or My Documents folder, ThinApp saves the documents to the physical system. ThinApp sets the isolation mode in the ##Attributes.ini files in %Personal% and %Desktop% to Merged even when you select WriteCopy isolation mode.
Applying Merged Isolation Mode for Modifications Outside the Package
With Merged isolation mode, applications can read and modify elements on the physical file system outside of the virtual package. Some applications rely on reading DLLs and registry information in the local system image.
The advantage of using Merged mode is that documents that users save appear on the physical system in the location that users expect, instead of in the sandbox. The disadvantage is that this mode might clutter the system image. An example of the clutter might be first-execution markers by shareware applications written to random computer locations as part of the licensing process.
When you select Merged isolation, ThinApp completes the following operations:
Sets the DirectoryIsolationMode parameter in the Package.ini file to Merged.
ThinApp retains Merged isolation mode for the %SystemSystem%\spool subdirectory by creating an exception to the %SystemSystem% parent directory isolation mode.
Between the prescan and postscan capture operations, assigns Full isolation mode to any directories that the application creates during the installation. This process is unrelated to the isolation mode of any new directories that the running virtual application creates.
Merged isolation mode in the Setup Capture wizard has the same effect as Merged isolation mode in the Package.ini file, including the directory exceptions that specify WriteCopy isolation mode. The Setup Capture wizard and manual capture process with the snapshot.exe utility configure the directory exceptions for you with the ##Attributes.ini files within the directories.
Applying WriteCopy Isolation Mode to Prevent Modifications Outside of the Package
With WriteCopy isolation mode, ThinApp can intercept write operations and redirect them to the sandbox.
You can use WriteCopy isolation mode for legacy or untrusted applications. Although this mode might make it difficult to find user data files that reside in the sandbox instead of the physical system, this mode is useful for locked down desktops where you want to prevent users from affecting the local file system.
When you select WriteCopy isolation in the Setup Capture wizard, ThinApp completes a number of operations.
Sets the DirectoryIsolationMode parameter in the Package.ini file to WriteCopy.
Between the prescan and postscan capture operations, assigns Full isolation mode to any directories that the application creates during the installation. This process is unrelated to the isolation mode of any new directories that the running virtual application creates.
WriteCopy isolation mode in the Setup Capture wizard has the same effect as WriteCopy isolation mode in the Package.ini file, including the directory exceptions that specify Merged isolation mode. The Setup Capture wizard and snapshot.exe utility configure the directory exceptions for you with the ##Attributes.ini files within the directories.