DeSynthed

Sorry but i need help. I have been using Technic launcher for a while Voltz Specifically, recently when I log in FML does whatever it has to do then all the sudden a checkerboard flashing screen, this occurs on any modpack, Troubleshooting I've done: -Deleating my technic folder. -Re downloading the launcher -adding other packs -check java for 64bit -use the download files for the vanilla launcher Interesting fact, -prior to the voltz update i manually was playing voltz through the vanilla launcher (since the update I can't get the correct filles swapped in) - It seems that not all the files are downloading (due to the fact that it doesn't work in vanilla mc launcher) THIS IS A MAC THAT I AM USING not a PC. and please I need help.