How to Install Windows 8.1 on Haswell Mac?
This is how to fix the bootcamp windows install error:

"Windows could not update the computer's boot configuration."

Do not try to fix with a workaround - you'll find solutions of people manually selecting their Windows partition during reboot by holding down the OPTION key. This will work, but you are circumventing the way that apple wanted you to install it (via EFI).

The solution to this error is simple: it's a PRAM problem. I've seen a lot of different ways of people claiming to fix this problem. I've experienced it multiple times on my Haswell 15" retina Macbook Pro, but it seems to be affecting a lot of the other Haswells as well.

Here are the steps:


Create a USB install like normal using Boot Camp Assistant
(include the Apple support software)
Partition your drive for OSX and the new BOOTCAMP partition
Let it automatically reboot, follow the normal procedures to format the new BOOTCAMP partition, and get to the "finishing" step during the Windows installation. You will get the error
At this point, when you press OK it will automatically restart after 10+ seconds.  When that happens, quickly hold ALT+COMMAND+P+R. You will see
your screen flicker and you will hear the bootup sound twice, which means you reset the PRAM successfully
Your OSX install should now boot instead of the failed Windows install
Open Boot Camp Assistant again. Remove the Window partition that was created and restore OSX back to the partition size it had at the beginning of these steps
Go through the Boot Camp Assistant once more to create the BOOTCAMP partition. You do NOT have to recreate the USB, so just uncheck and skip those steps
Let it automatically reboot and follow the same Windows installation steps as before. You should not get the error the second time.


I found that this is the only thing that consistently works for me.  I've installed Windows 8 and 8.1 on Mavericks 10.9.2 Haswell Macbook a bunch of times, so I'm pretty sure of it. This will result in you installing it as Apple meant it to be installed.