Q: Reboot fail after installing El Capitan help!!

Samsung 850 Pro worked when originally formatted with OS 10.11 the failed after 10.11.6. At first could not write one bit and had 1TB left on this 2TB drive. Erase failed as well but read worked. Saved to backup and sent disk to seller. He refused to help and sent the SSD back. Tried to plug it in again just for grins and surprisingly it worked for write and read again and allowed format. Unfortunately it would never again allow OS X boot and froze at the white screen after progress bar completed. SO......

Bought an OCZ 490GB drive and decided to try mounting that with OS X 10.11.6 using Super Duper copy. Nope. Now trying USB boot with a fresh install. Waiting at this moment for it to complete. I called Apple, they said my .09 computer chipset is too old but I upgraded to '10 and 12 core 3.46. Computer boots fine from Seagate 7200 drive every time. THE SSD'S WONT WORK. I don't understand how they managed to screw up SSD's in El C but it has really cost me. I'm so disappointed I may revert everything and just use this machine tilt dies years from now and never buy another tower from apple again. Disgusted Audio musician producer!

Interesting.  There may be a new driver from Samsung you need to install.  However, the greater likelihood is that there is some old application or kernel extension that does not play nice upon boot up with your El Capitan updated drive that you need to remove.  Discovering what that is can be difficult.  I had a similar problem with a Toshiba Apple SSD drive installed in my 2009 Mac Pro.  Still have not rebooted from it now for months, waiting for another upgrade to further flush out the software.  Booting up from an external backup drive for now.