Can somebody explain to me about these three addon: True Addon Svcpack Addon RunOnceEx addon And, can we make addon with DX's Universal UpdatePack-Addon Creator [DXUPAC] Last, what's different between switchless installer and true addon/ svcpack addon? I'm really new to Addon Maker and Windows XP Installer Maker. I've ever use nLite and RVM Integrator but without addon inserted. Any help and answer is appreciated.