Elements 8 failing at first launch

Hi, hello am new here.

I just bought Elements 8 and it’s installed ok, but won’t run or, at best, it quits. It hasn’t run at all yet, since buying it.

I’m on a mac running El Capitan/10.11.5

I had some old plug ins which it’s encountering (and which I installed in error and they aren’t licensed as I tried to ditch them when realised error) and it can’t resolve, but I can’t find out where to uproot and delete them! The main ones are Softube ones but feel could be more. Have googled and there’s apparently an uninstaller but can’t find it.

Previous Cubase wasn’t bothered by them. Thanks… have contacted Steinberg support who just said to reinstall, effectively.