How to execute a Deferred PowerShell Custom Action only on install?

[gomochainstall]

I've added a PowerShell custom action which adds a Firewall rule to the system. However, it is always being added, on install, re-install and uninstall. Is there a public property that I can use to determine whether the application is installed for the first time on the system? 

[Revenera_Ian]

Hi @gomochainstall,

Thank you for your post.

If you are using a Basic MSI project or an InstallScript MSI project, not an InstallScript project, you could try using the Installed private MSI property.

Here is a link to the official Microsoft documentation about the Installed MSI property:

https://docs.microsoft.com/en-us/windows/win32/msi/installed

I understand that you requested a public property, but the Installed property is typically the property used for this type of condition.

The condition for a first-time install would be: NOT Installed

because you would be checking whether the product has already been installed. If the installer is running as a first-time install then the Installed property will not be set. Hence, you would be checking if the Installed property is not set.

Here is a link to our Introducing the Installer Cheat Sheets blog post, which has a link to a Common MSI Conditions Cheat Sheet:

https://www.revenera.com/blog/software-installation/installer-cheat-sheet-series/

Hope this help.

Please let us know if you have any questions or concerns. Thanks!

[gomochainstall]

Thank you! I've got it working. But now I have a different question, what if I want to remove the firewall rule only on uninstall? The 'Installed' property will also have a value on a reinstall so I can't just remove it when 'Installed' has a value. 

[Revenera_Ian · Accepted solution]

Thank you for your reply.

You are welcome, @gomochainstall! I'm happy to hear that you've got it working.

If you are using a Basic MSI project or an InstallScript MSI project, not an InstallScript project, you could try using the REMOVE public MSI property in the following condition:

REMOVE~="ALL"

That condition will only evaluate to true only during uninstall.

Please give this condition a try, rebuild your project, then retest this issue. Does this issue still occur?

Please let us know if you have any questions or concerns. Thanks!