I have the techniclauncher on my mac. It works fine sometimes, and sometimes not. When it doesn´t work, it goes like this: I open the launcher, and select the tekkit classic pack. I click "launch" and then it loads up, and theres a white screen , saying "tekkit classic" on the top, and then it just dissapears and closes the launcher to the desktop. And sometimes compeletely random without me doing anything, it works. But it never opens two times after one another.