Some have taken me to task over sharing what I found. My acer did the same and I tracked it down to something plugged into the USB ports. I unplugged all USB devices and the update succeeded as well as the next boot.

I will not enter into any argument here. I will only share my success.

-> If that doesn't work, call Acer and ask for a fix.

In closing there was another failure but it was not a Microsoft or Acer issue. The machine had been damaged (the OS) by trojans. We had to restore the PC then install the updates. Again some take Microsoft to task over this.
Bob