Black screen after 2016-001 update

I Just tried updating to the 2016-001 security update on a MacBook Pro from mid 2014. After restart and a status bar showing the update, a black screen appears. The cursor moves but nothing else works and the computer appears to be stalled. This is the second time it happened today. I reinstalled the OS after the first try. It appears I will have to do that again to have a working computer. Is this update defective?