I haven’t used blender for few weeks and when I go to open the software, it keeps crashing. I have to go back to version 2.76a to get a copy of Blender that will open and start-up. I had been using 2.78rc 64 bit for Mac but now it crashes on opening.
Any thoughts or suggestions?
I now have this resolved.
If you have an issue with Blender and are running a Mac Sierra OS, Nvidia graphics card, try updating your drivers for CUDA. It seemed to resolve the issue.
I am begining to wonder if there has been a dodgy display driver download from Nvidia as i had an issue not so long ago with my sound glitching. I use HDMI and the audio in that to my TV.
I reinstalled windows and it was fine, Nvidia updated and the problem has started reoccuring. I will keep an eye on my system and if it occurs again i’ll try a driver rollback and see if i can get a driver version number to avoid if its related.
Thanks for the info Morgaine 
Most welcome!
I really can’t take a lot of credit for this solution other than doing a bit of research
and looking at some suggestions and trying them from Blender.org. I haven’t had the sound glitching issue that I know of but I don’t usually run a lot of sound…only the occasional iTunes or Shoutcast run through headphones.
For those with more computer literacy and want to review the thread and associated solutions, you can find it at the following link https://developer.blender.org/T51808. I should of added this in the beginning but was on my way out the door. With Macs, it can be difficult to find solutions to issues but, it’s a lot better than it use to be when it comes to resolving issues. 
Hopefully, it will help someone else not tear their hair out trying to figure out the issue.