ReplacedInUseFiles
The installer sets this variable if it encounters an in-use file that must be replaced. In that case, a reboot is required to complete the installation.
Usage
Used internally by the installers. You can refer to this variable as <ReplacedInUseFiles>. In conditional expressions you can omit the brackets and simply use ReplacedInUseFiles as a test for delayed file copying. Set automatically by all installers.