I am attempting to install Windows 8.1 on my machine (a mid 2014 MacBook Pro running El Capitan) and I keep running into a BootCamp error in the first step that says
The startup disk must be formatted as a single Mac OS Extended (Journaled) volume or already partitioned by Boot Camp Assistant for installing Windows.
However, the startup disk is partitioned as a single HFS+ partition as verified by the output below:
$diskutil list /dev/disk0 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme *500.3 GB disk0 1: Apple_HFS MAC HDD 499.9 GB disk0s1
Why does Boot Camp think my disk is not partitioned correctly?
I've read several posts about this error message, but all describe how to repartition the drive instead of why a correctly partitioned drive may cause this error.