Symantec WINDOWS INSTALLER EDITOR 8.0 Reference page 347

Windows Installer Editor Reference
3. In Instance Property, enter a property that will be replaced by a unique value in
this instance of the installation.
4. Product Name is pre-filled with the product name from the Product Details page. If
you change it here, it is changed on the Product Details page.
5. Click Add at the right of the page.
The Instance Transform Details dialog box appears.
6. Complete the dialog box:
Instance Property Value
The base product name is incremented by 1 for each new instance transform.
You can change this but the value must be unique. This value will replace the
instance property and serve as the instance identifier.
Product Code
Windows Installer Editor generates a product code in the form of a GUID, which
ensures that no two applications ever have the same product code. To change
the product code, click Generate; typing or editing a GUID does not generate a
valid GUID.
Product Name
The base product name is incremented by 1 for each new instance transform.
You can change this but the name must be unique. The end user sees this name
during installation and in the Add/Remove Programs dialog box.
File Name
The base product name is incremented by 1 for each new instance transform.
You can change this but the name must be unique. This becomes the name of
the transforms that is created. The transform is saved in the same directory as
the base installation file.
Change install directory to Instance Property Value?
Mark this to change the value of the directory property INSTALLDIR to the value
in the Instance Property Value field above. INSTALLDIR is the main
installation directory for the application (example: Program Files\Application).
This helps you isolate files for each instance.
Example: Suppose you want to install test, beta, evaluation, and production
versions of your application on the same destination computer. To do this, code
your application to look for these instances. Add files to the installation. On the
Instance Transforms page, add instances for each version of your application
and define an instance property value for each (examples: 1, 2, 3, 4). Mark the
Change install directory to Instance Property Value check box for each
instance. When each instance transform is applied to the installation, files are
installed into INSTALLDIR, but the value of INSTALLDIR changes based on the
instance property value. (Examples: Program Files\Application1, Program
Files\Application2, and so on.) If you did not mark the Change install
directory to Instance Property Value check box, then files for each instance
would be installed on top of each other in the same directory as for the base
installation.
7. Click OK.
The instance transform is added to the list on the Instance Transforms page. To edit an
instance transform, double-click its name. The actual transform files (.MST) are created
during compile.
Merge Modules and Transforms
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