If you're having an issue getting your Symphony I/O to show up properly in Apogee Maestro and the exclamation mark (!) icon stays on the front-panel, there are a few troubleshooting steps to check, depending on what Audio Interface Mode you're using.
USB Audio mode
1. Confirm that your firmware and software is up to date and that the versions match. Click here and follow these instructions.
2. Confirm that your Symphony I/O is in 'USB Audio' mode by pushing in and holding on the right-side front-panel encoder and scrolling through the different modes until you get to 'USB Audio' and then push in on the encoder again to restart the unit in 'USB Audio' mode.
3. Confirm that you're using the Apogee USB cable that was included with the Symphony I/O. Unplug USB cable and then plug back in to a different port and restart your Mac.
4. Power-cycle Symphony I/O.
Symphony mode (Symphony 64 PCIe or Thunderbridge)
1. Confirm that your firmware and software is up to date and that the versions match. Click here and follow these instructions.
2. Confirm that your Symphony I/O is in 'Symphony' mode by pushing in and holding on the right-side front-panel encoder and scrolling through the different modes until you get to 'Symphony' and then push in on the encoder again to restart the unit in 'Symphony' mode.
3. Launch Audio MIDI Setup (Applications Utilities Audio MIDI Setup). We recommend using Audio MIDI Setup instead of System Preferences Sound. Make sure that ‘Symphony64′ (PCIe or Thunderbridge) is selected in the left-side column. In the ‘Source’ menu on the right, choose the appropriate port selection depending on how many Symphony I/Os you have. If you have 1 unit, choose ‘Port 1: 32ch’… if you have 2 units, choose ‘Ports 1-2: 64Chs’. Quit Audio MIDI Setup and restart the computer.
4. If you've gone through the above steps and the exclamation mark (!) icon still remains on the front-panel, there is a chance that the PC-32 port on either the Symphony I/O and/or the Symphony 64 PCIe/Thunderbridge isn't making a complete connection and needs to be cleaned with rubbing alcohol.
Follow these instructions:
Disconnect the PC-32 cable ('Symphony' or 'Digi-Link' cable) and apply some rubbing alcohol (isopropyl) to the pins on the inside of the PC-32 cable's connector end. Make sure to apply the alcohol to the top and bottom of the pins on the connector.
Now plug in and unplug the cable to the 'Main' port of the Symphony I/O. Do this about 20 times, so the port gets clean. Now repeat this with the Main port on the Symphony 64 PCIe or Thunderbridge.
After each port has been cleaned, reconnect the PC-32 cable, power-cycle the Symphony I/O, and restart your Mac.