Prior to installing macOS 10.12.5 I had enabled reading AND writing my Bootcamp partition (formatted NTFS) with terminal.
For those who aren't familiar
sudo nano /etc/fstab [ENTER]
LABEL=BOOTCAMP none ntfs rw,auto,nobrowse
[control-o]
[ENTER]
[control-x]
[ENTER]
Then use "open /Volumes" to...