I just tried the update again...
First I run the troubleshooter
I deleted most of the devices and let Windows recreate the devices...
I then did the install using the media site to do the update
same results.... It fails at 45%
so frustrating
I am having the same problem. Read somewhere (can't execute this yet as it is an office laptop and need to finish several things first before trying again), that you should disable on the Device Manager the USB WiFi and also disable your Video Card.
A few guys couldn't pass the 45% until they did this and then it worked but they could never tell who was the culprit.