Symphony I/O MkII Thunderbolt is not recognized in Symphony Control (macOS Big Sur, Monterey, Ventura)

If your Symphony I/O MkII Thunderbolt is not recognized in Symphony Control application (in macOS Big Sur/Monterey/Ventura), then this is the guide you want to follow along.

This procedure is only for those using the previous "Symphony Control" software. It does not work for those using "Control 2" with their Symphony I/O MkII.

1. Confirm that Symphony is recognized in PCI and Thunderbolt in  > About This Mac > System Report > Hardware, but not in Audio (as seen in the screenshots below):

System Report showing Symphony is recognized

System report showing PCI details of Symphony Thunderbolt

System report showing Audio details and devices on Mac

2. Open Activity Monitor in Finder > Applications > Utilities.
In the View menu, make sure "All Processes" is selected, then search "Apogee" in CPU to find "Core Audio Driver (ApogeeSymphonyIO2T.driver)":

Activity Monitor showcasing Core Audio Driver usage on Mac

3. Double Click "Core Audio Driver (ApogeeSymphonyIO2T.driver)" then "Force Quit" the process:

How to Force Quit the Core Audio Driver on Mac

Click Force Quit to stop the Core Audio Driver

4. After "ApogeeSymphonyIO2TSymphony.driver" restarts itself, Symphony Control.app will recognize Symphony!

Symphony Control App recognizing unit after force quit