So after trying ever solution I can find on the internet, I am finally breaking down and posting this in hopes of a solution I couldn't find. In advance, I appreciate anyone who is willing to help me with this. Whenever Mountain Lion came out, I upgraded to it. However, I found very quickly that Logic Pro 9 and ML did not get along. After searching around, I found that this was a common problem and that the only thing to do was to downgrade again. As we all know, that is no easy task, however, I finally found a way and was back on Lion again, and Logic worked great again. The problem is, somehow when I downgraded, my Firewire port stopped working. It wont recognize my Hardrives that I plug in. It worked when I was originally on Lion and it worked for my short time on ML, but after the downgrade, it was no more. I found it hard to believe that the port went out completely since everything I was doing was on a software level. Over the last yearish, I have tried many solutions to this, including: Restarting the computer Power Cycling the computer Plugging in different harddrives (I have a Portable Lacie 500GB, and a 2TB G-Drive) Trying different Firewire cables Resetting the PRAM Resetting SMC My friend who works at SimplyMac even gave the official apple diagnostic disc that they use to find problems on computers. Not one test failed. So I am out of ideas, and would love if someone knew of anything else. I dont want to accept that my firewire port went bad during the downgrade since it just seems completely illogical, but I am about there. I have last years iMac, not the newest one. Model # MC813 16GB RAM 1TB HD Intel i5 Thanks you very much for any help you can provide, even if it is a confirmation that my firewire port is in fact shot. One last thought that occurred to me while writing this. My iMac has 2 thunderbolt/minidisplay ports on it. What I am wondering is, are these actually functional thunderbolt ports, or do they only work as mini display? And if they are thunderbolt, can I get a thunderbolt to firewire adaptor and solve all my problems that way?