I've been trying to resolve this issues for quite some time. TransType doesn't err; it simply stops processing in the middle of a conversion. This is not one font; it's all different fonts. I've tried fonts from Adobe and other foundries. It will only convert a few.
It starts a conversion and the progress bar appears. then it simply hangs.
Now, I am on Yosemite and according to FontLab support, there are no problems. Honestly, I think there are and it might relate to other applications or font packages on the machine.
We tested by installing it on a Mavericks machine and it worked perfectly.
We have tested many different fonts. Not all hang, but quite a few of them do. And yes, I have submitted fonts that didn't work for me to FontLab and found they converted fine on their machines with Yosemite.
I've been trying to find a solution for some time, so if anyone has thoughts on this, I'd love to hear them.