Setting Up Max for Live
Please follow these steps to download, install and authorize Max for Live:
After purchasing Max for Live, download, install and launch Live 8.1 (or newer) — this is important as Max for Live won't work with earlier versions of Live.
Re-authorize Live. This will also activate Max for Live.
Open Live's Device Browser and double-click on Max Instrument, Max Audio Effect or Max MIDI Effect:

Download Max from the link shown in the device and install it.

Re-launch Live. (Don't launch Max. Live and Max communicate internally and you will never need to launch the Max application manually when using Max for Live.)