I've been working hard to find a Professional to assist you with your question, but sometimes finding the right Professional can take a little longer than expected.
I wonder whether you're ok with continuing to wait for an answer. If you are, please let me know and I will continue my search. If not, feel free to let me know and I will cancel this question for you and refund your deposit.
Please note, I am just a moderator for this category, I can only try and find experts to help, I can't answer the question itself.
Thanks for replying.
We will continue to look for a Professional to assist you.
If you decide on a refund, or wish to keep the credit for a future question, then of course we'd honour it.
Thank you for your patience,
Sorry for my delay in reply - your last mail went straight to my junk box. I am running OS X 10.9.1.
I have installed the latest Tascam driver and firmware from their site, and installed them as per their published instructions. The unit was running fine on Mountain Lion.
Thanks for your response... Yes, unfortunately, I have uninstalled all previous drivers using the installer provided by Tascam - three times now. The only thing I can think of doing is deleting any elements of the Tascam drivers manually and trying another re-install. Just worried about missing an element and getting no further forward.