Unity 4.6.x crashes on load OS X Yosemite

Hey everyone- I'm running into an issue that seems to be specific to 4.6.x versions of Unity. First, the specs: I'm running a Mac Mini with an i7 Processor, 8GB of ram and OS X Yosemite.

Now, I've been able to run Unity 5.x without any issues (This is my last resort, it's not ideal as I'd rather run Unity 4.6.x, please do not ask me why, it's not relevant to the issue at hand. If I have to I'll end up running Unity 5.x), but when I attempt to run any Unity 4.6.x version, the application attempts to start up, and immediately crashes. I've attempted uninstalling & removing preferences, rebooting, different versions, etc to no avail. Has anyone run into this issue before, if so what was the fix? I've heard that this was a known issue at one point, but was fixed in Unity 4.6.1 (which I've attempted to run unsuccessfully...)

Thanks!