Security Update 10.13.6 Failed

I have a MacBook Air 4,1 running High Sierra 10.13.6. I attempted to load the most recent security update 10.13.6, which resulted in the screen going black with only the cursor visible. The cursor is moveable. I had to force a shutdown to gain access. Every time I shutdown the device I get the black screen with the cursor and I have to force a shutdown. How do I get this update loaded or how do I unapply what has been done so far?

Thanks

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