If this per-machine system policy is set to 2 (two), Windows Installer uses the FilesInUse Dialog. This setting disables attempts by the Restart Manager to mitigate restarts when installing a Windows Installer package that has not been authored to use the Restart Manager. The installer still uses the Restart Manager to detect files in use by applications.
The DisableAutomaticApplicationShutdown policy is available beginning with Windows Installer version 4.0 on Windows Vista.
Build date: 11/30/2012