Why not upgrade OSX.
Did you use the scrict procedure ? There’s a known problem with mac witch is USB ground and OT. So there’s a plug order (like rewire order if i can describe like that)
- Power the MAC (wait for it’s ready)
- Plug the OT usb (but OT is power off)
- Switch on the OT
- Go in system activate USB Disk mode (at this point OT mount if not upgrade your OSX)
- Eject everytime the OT by drag and drop on the trash to eject.
Then workaround is cheap card player