WiX 3.7: How to add or update a dialog during uninstall?

Question

I need to add a dialog box that would pop up during complete uninstall (not major upgrade) right after the confirmation ("Are you sure you want to uninstall this product?") dialog. This dialog would prompt the user to answer a question and based on the response, set up a property that would be used in the condition for the RemoveRegistryKey element (i.e. it will remove a registry key only if the user selects an option to delete the key).

I have an idea how to add a dialog to the install sequence (I am using a modified WixUI_InstalLDir sequence to which I added a custom dialog I need during installation), but I can't find any references that would explain how to add a custom dialog to an uninstall sequence. It would be even better if I could modify the uninstall confirmation dialog, so the user would see one dialog instead of two. An the key thing would be to be able to set up a property that could be used in the component condition.

Is this possible? Are there any examples how to do this?

Answer 1

This is against Microsoft design guidelines. Add/Remove programs calls the uninstall with a silent UI argument and the UI sequence is never processed.

The only place you can author UI during an uninstall is a "change" or "maintenance" UI experience where they select Repair | Change | Remove and on Remove do your UI. But you'd have to lock down the Remove buttom and force them through this path. Also realize they could call msiexec /x /qb from the command line.

Bottom line is Microsoft made this choice to make the uninstall process simple and easy for the user. As for removing the registry key, Microsoft would say that you should leave user data on uninstall.