It looks like your Windows is missing the BCD.
Grub2's os-prober looks for the Windows boot partition that has boootmgr & BCD.
If you can run Windows repairs from you Windows installer it should create a BCD. Or you may need to download something like EasyBCD, but I do not suggest using EasyBCD to dual boot.
BCDboot Command-Line Options Windows Vista/7/8 recreates boot files.
Windows repair console:
How to use the Bootrec.exe tool in the Windows Recovery Environment to troubleshoot and repair startup issues in Windows