Mac shuts down after loading bar loads 50% I purchased a new Mac (Apple iMac MK142LL/A - Intel Core i5, 1.6Ghz, 21.5 Inch LED, 8GB, 1TB, Intel HD Graphics 6000, OS X El Capitan). It worked fine the first day. 

Since today, when I try to start the iMac, it shuts down automatically after the loading bar loads 50% in the grey screen. After that it will not start until I unplug the power cable and plug again. Same thing again and again.
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.