Understanding File Overwrite Rules

InstallShield 2009

Project

This information applies to the following project types:

Basic MSI

InstallScript MSI

Web

The Windows Installer service uses several file overwrite rules, by default, to determine whether a file included in an upgrade should overwrite a file that already exists on the target system. The rules apply when the REINSTALLMODE property uses the o setting to install over older files on the target system. To change this behavior, you can replace the o option with one of the following values:

p—Reinstall only if there is no equivalent file on the target system.

e—Reinstall if the file is missing or if it is an earlier or equal version.

d—Reinstall if file is missing or different.

a—Reinstall all files, regardless of version.

Note that the setting for REINSTALLMODE applies to all of the features being installed; it cannot be set for an individual feature. In addition, setting REINSTALLMODE to include a will likely cause prompts for the original installation source during the application of a patch.