A solution that works for Windows 8.1 on MBP Late 2013
Here is how I could successfully install Windows 8.1 on Mbp Late 2013 running Maverick:
Follow precisely these steps and you will be done in 30 minutes:
1/ Using BootCamp Assistant, create a USB stick and select all three options including Bootcamp updates, etc.
2/ Set your partition size when asked.
3/ IMPORTANT: When reboot, Hold the Option key and Boot again on Maverick (do not boot on the USB stick)
4/ When back on Maverick, run Disk Utility, select Macintoch partition and choose Partition tab.
5/ Select the BOOTCAMP newly created partition (the one at the bottom) and press minus ➖ to remove it.
6/ Apply for changes. At this point, BOOTCAMP partition should be gone.
7/ Press + to add a new partition that will likely be called Machintoch HD2 or so.
8/ Rename it to BOOTCAMP
9/ IMPORTANT: Change the partition type to ExFAT.
10/ Apply again for changes.
11/ Reboot your Mac and Press Option again. Select WINDOWS (Orange USB device)
12/ Windows installation process should start and bring you to the partition selection.
13/ Select the BOOTCAMP partition (the one at the bottom) and FORMAT it.
14/ Press Next and get going through Windows 8.1 installation.
15/ IMPORTANT: Each time a reboot occurs, press Option key and select WINDOWS Drive (NOT the ORANGE USB stick)
16/ Finally, Windows 8.1 will get installed and will ask for BOOTCAMP drivers to get installed. Just follow the instructions.
17/ You are done.
P.
MACBOOK PRO (RETINA, 15-INCH, LATE 2013), OS X Mavericks (10.9)