I have two 1TB HDDs in my Mac Pro, and since two days ago one is in whole El Capitan and other is Bootcamp, Win7. I want to make one partition on each disk, HFS Data on El Capitan disk and exFat Data on Bootcamps disk (to be for both OS'). In El Caps Disk Utility Bootcamp HD is greyed out and i cannot touch its partitions. Should i do it from Win or some third party app from OS X? I wanted to ask first, because last time i messed with Windows' Utility on Mac, i somehow managed to change partition table and OS X couldn't read that disk anymore. Didn't know should i ask here or in OS X sub forum... Thanks!