After unclean Windows shutdown in Boot Camp or Virtual machine based on Boot Camp, you will not be able to see Windows partiton, if you have NTFS-3G installed
NTFS-3G intercepts all Mac OS ntfs driver calls, and manage NTFS partiotions on boot, or after Virtual machine is stopped.
If Windows was not cleany shutdown, NTFS-3G doesn't mount dirty NTFS volume by default.
Please start Windows in Virtual Machine or directly in Boot Camp, and perform disk check using chkdsk utility
chkdsk DriveLetter: /f /r
or GUI utility from disk properties and select repair errors option.
Please note, that you need to restart Virtual machine, or Windows in Boot Camp to finish process.
After you logon to Mac OS, or stopped Virtual Machine, sometime it is still necessary to mount Windows partition from Disk Utility