Follow the directions below to reset your Apollo Twin MkII hardware:
1. Turn off the Apollo Twin and computer.
2. Disconnect any cables connected to the Apollo Twin except the power cable (this includes disconnecting the Thunderbolt cable). If there are any monitor speakers or headphones connected to the Apollo Twin make sure that they are either disconnected or powered off before continuing.
3. While the Apollo Twin is powered off press the following buttons - the PREAMP button, the Polarity (Ø) button and the Low Cut Filter Button (see picture below for reference)
4. Keeping the buttons pressed down, turn on the power switch to the Apollo Twin - hold down the button combo for approximately 10 seconds until the LED lights on the front panel of the Apollo Twin stop flashing.
5. Once the LED lights stop flashing you can release all three buttons, shut down the Apollo Twin once more, and reconnect all cabling. Reboot the system like normal.