Guest post by my least favourite colleague, Tom.

Normally - but not always - people want to run a program just after the install it - you can help then to do this by using an opt-out system with a checkbox checked by default

To create the checkbox and control whether it is set you must use the following properties in your Product section:

Id="WIXUI_EXITDIALOGOPTIONALCHECKBOXTEXT"
Value="Launch the cool program"
Id="WIXUI_EXITDIALOGOPTIONALCHECKBOX"
Value="1"

The value of WIXUI_EXITDIALOGOPTIONALCHECKBOX controls the checkboxes checkedness.

You then need a custom action to do some launching:

Id="LaunchApplication"
BinaryKey="WixCA"
DllEntry="WixShellExec"
Impersonate="yes"

and some UI wiring in the UI element under the Product element to get you custom action called.

Control="Finish"
Event="DoAction"
Value="LaunchApplication">WIXUI\_EXITDIALOGOPTIONALCHECKBOX = 1 and
NOT Installed

Huzzah - you now may have a working installer.