Hi Frank,
In the
Custom Actions view you can add a custom action that display the related message. Also, the custom action should be executed during a
Regular Uninstall, thus the custom action will execute during a complete uninstall of the application, not during an upgrade.
So, in the
Custom Action Properties, expand the
Show upgrade options from the
Execution Stage Condition section and select only the
Regular Uninstall option.
Please let me know if you need any help.
Best regards,
Dan