Q: Logic Pro 9 will not start in Mountain Lion

I have gotten so much great info here, that I thought this would be the best place to ask my question. I am using a Mac Pro 3, 1 (early 2008). I bought the machine running Leopard, upgraded to Snow Leopard, lion, and Mountain lion with no problems. I have a valid license for logic studio eight and nine. Logic ran without problems… Until I upgraded to Mavericks. After upgrading, my computer started acting terribly. It was much slower, and I would get these terrible freezes where the screen would go kind of crazy flashing colors and stop working completely.

After thinking it was my graphics card, and not wanting to spend $1 million on a new video card, I decided to try downgrading back to Mountain lion.

First, I cleaned off the system drive, and installed mountain lion fresh from a USB drive. The crashing went away and the computer ran much faster and smoother.

However, after reinstalling logic, I am no longer able to start it. As soon as I click on the icon either through Finder or a dock menu, it crashes almost immediately. It has never gotten to or through the part where it scans the plug-ins or anything. I tried to understand the report it generates, and understand the things that it is trying to tell me, but cannot make any sense out of what it is actually saying happened. I have updated the app as well. I am currently at 9.1.8.

I don't know why this is happening, and don't know what the best next step should be. I already have everything moved out of the way if I need to do another fresh install. I was thinking to try a fresh install on a clean drive of Mavericks, and see if anything changes. Also, when I would try to change logic to start in 64-bit mode, there would be no option in the "get info" window to select or deselect 32-bit mode. It simply wasn't there.

I can post specs/logs/error reports of course, but don't even know where to start. Does anybody have any experience with this? Does anybody have a suggestion for where to start? Do I need to get Logic X? (Logic was running fine in Mountain Lion before) I have scoured the Internet trying to find someone with similar issues, but haven't found anything that works. All I have really tried is reinstalling both the OS and the app. Everything else works great in Mountain lion. I still have my Snow Leopard disks if you think going all the way back there would be the best option. My OS is running in 64-bit mode, but when logic does try to start, it says 32-bit mode in the little start up window.

I'm totally comfortable with Terminal, Console, etc, so can provide any info if anybody thinks they may be able to direct me towards a solution.

Thanks for reading and thanks for any help or advice.