cubase 8 will not start up

i just updated from cubase 6 to 8 and it keeps quitting unexpectedly when i start it. cubase 6, reason, and logic loads up fine. i have an iMac running yosemite. tried disk repair permissions to no avail. with earlier versions of cubase i was able to get someone on the phone and the problem would be quickly resolved, but it seems their tech support isn’t what it used to be … has anybody had problems with cubase 8 loading up on iMac?