The simplest approach is to avoid inconvenience of the raw WiX and use Wix# ManagedSetup.
- Create a "WixSharp Managed Setup - Custom UI" project with VS Wix# templates (https://wixsharp.codeplex.com/wikipage?title=Visual%20Studio%20Project%20Templates)
- Now you can place any WinForm control (e.g. checkbox) in your ExitDialog.
- On closing the dialog you can either run the application directly with Process.Start. Here you can also chose to start the process elevated if required.
void finish_Click(object sender, System.EventArgs e) { if (runAfter.Checked) try { Process.Start(Path.Combine(MsiRuntime.InstallDir, "myproduct.exe"); } catch { } Shell.Exit(); }