Mac shuts down after loading bar loads 50%
This is something that you should absolutely contact Apple about since it is a brand new Mac - it is under warranty and will be replaced, if it's in the first 14 days you can even return it to the Apple store &amp; get a brand new one (or your money back) with absolutely no questions asked.

If you do want to troubleshoot this, try to boot in verbose mode by holding command+v during startup - take a picture &amp; post it as a comment here.