If you find that the APC mini mk2 is working as a MIDI controller, but the LEDs are not responding as expected, this is often related to the Control Surface used in Ableton.
Firstly, please ensure you are using Ableton version 11.2.7 or later, as this is the version that introduced control surface support for the APC mini mk2. Earlier versions can still work with the device (for example via custom MIDI mapping), however the mapping that supports the LED functionality would not be present.
Next, please select the control surface as follows, from within the Ableton MIDI Preferences:
The APC mini mk2 will now be set-up for use with Ableton, with full LED functionality. If you experience any issues with the device set-up, please do not hesitate to contact our support team HERE.