Summary

This article explains how to create an install condition based on a specific registry entry.

Synopsis

How to create an install condition based on a system search to detect whether a registry entry exists using Installshield. This install condition in the example below is useful for checking for the existence of another Basic MSI installation on the target machine. The install condition should only allow the installation to continue if the other Basic MSI installation does not exist on the target machine.

Discussion

In order to create the install condition and the corresponding system search, follow these steps:

1. Open your Basic MSI project in the Installation Designer view of the InstallShield IDE.
2. Navigate to the Behavior and Logic > System Search view.
3. In the top, right-hand white area under the System Search columns and under any existing system search entries, right-click.
4. Click Add...
5. At the introduction screen to the System Search Wizard, click the Next button.
6. Select Registry entry from the dropdown box.
7. Click the Next button.
8. Select HKEY_LOCAL_MACHINE from the Registry Root dropdown box.
9. Copy and paste the following value into the Registry Key field: SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{00203668-8170-44A0-BE44-B632FA4D780F}
   (The value in curly braces should be the Product Code of the other Basic MSI installation being detected by the system search.)
10. Set the Registry Value field to the following value: UninstallString
11. Click the Next button.
12. Under the Store the value in this property field enter the name of the public property that will store the result of the system search. For this example, name the property as follows: SAMPLEPROPERTY
13. Select the Store the value in the property and use the property in an Install Condition radio button.
14. Click the Finish button.
15. Navigate to the Installation Information > General Information > Product Properties view.
16. Double-click the field next to the Install Condition label.
17. Set the condition to the following modified value: Not SAMPLEPROPERTY
18. Set the desired message under the Message column corresponding to the row with the Not SAMPLEPROPERTY condition.
19. Click the OK button.
20. Save the project.
21. Build the project.
22. Test the installer.

If the system search and install condition are configured correctly (as described above), the installation should only continue if the other Basic MSI installation is not detected through the presence of the previously specified registry entry (from steps 8-10) on the target machine. Otherwise, the installation should display the previously specified message (from step 18).

Every Basic MSI project should have a default value for the UninstallString Value name similar to the following: MsiExec.exe /l{<Product Code>}

It is important to specify a Registry Value in the System Search of a Value Name that always has a default value. If a Registry Value is not specified, the System Search will check the value of the Default Value Name, which most likely will have a null value. If a null value is returned by the System Search, the specified property will be set to null. As a result, the Install Condition based on the System Search will not evaluate correctly.

Additional Information

• For more information on Adding a System Search, see the InstallShield Help Library topic Adding a System Search.
• For more information on using the System Search view, see the InstallShield Help Library topic System Search Wizard.