Understanding Isolation Modes
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Thinstall's Isolation Modes help solve the following classes of problems:

Problem 1: Application fails to run due to previous or future versions existing simultaneously or not uninstalling correctly
Solution: Thinstall "hides" host PC files/registry keys from the application when the host PC files are located in the same directories/subkeys created by the application's installer. Thinstall calls this Full Isolation; for directories and subkeys that have Full Isolation, the application will not be aware of any of the host PC's files that might exist, and the application sees only virtual files and subkeys at fully isolated locations.

Problem 2: Application fails because it was not designed or tested for multi-user environments and expects it can modify files and keys without impacting other users
Problem 3: Application fails because it expects write permission to global locations and was not designed for locked-down desktop environments found in corporate environments or Windows Vista.
Solution: Thinstall makes copies of registry keys and files written by the application and performs all the modification in a user-specific sandbox. Thinstall calls this WriteCopy Isolation; for directories and subkeys that have WriteCopy isolation, the application can see both the host PC's files and virtual files; however, all write operations will convert host PC files into virtual files in the sandbox.

Thinstall has 3 different isolation modes, which are automatically determined by SetupCapture. SetupCapture has a few simple rules for determining what isolation mode to apply to a registry subtree or directory during capture.

- If the application created a new directory or registry subtree during its installation (on a clean PC), the isolation mode is set to Full Isolation
- User-specific storage areas like the Desktop and My Documents are set to Merged Isolation so the application has direct write access to these locations
- All other directories and subkeys will default to WriteCopy Isolation
Note: Network shares are not affected by isolation modes; read and write operations to network shares occur unchanged by Thinstall.

For example, the following image shows a section of the Windows registry for a PC which has various older Office applications installed. Office 2003 creates the registry subtree:
Registry as seen by Windows Regedit


When running a thinstalled version of Visio 2007, Thinstall will set the HKLM\Software\Microsoft\Office registry subtree to Full Isolation. This setting prevents Visio 2007 from failing because of registry settings that may pre-exist on the host PC at the same location.

Registry as seen by Thinstalled Visio 2007