Declan The Elf

Whenever I try to launch a modpack that I recently installed for the first time it quits right before the Mojang screen pops up. I havent used technic launcher for a while and now I cant play any new packs. Im using a mac and have already reinstalled the packs, unistalled old ones I dont play, restarted the technic launcher, and none of that is working, please help!