ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
brew update
brew install caskroom/cask/brew-cask
brew cask install osxfuse
brew install homebrew/fuse/ntfs-3g
sudo nvram boot-args="rootless=0"
And reboot.
sudo mv /sbin/mount_ntfs /sbin/mount_ntfs.original
sudo ln -s /usr/local/sbin/mount_ntfs /sbin/mount_ntfs
Based on: http://apple.stackexchange.com/questions/152661/write-to-ntfs-formated-drives-on-yosemite
all commands executed, no errors but still can't write to external flash disk