Mac won't boot Windows partition after using disk utility I needed more space on my Windows partition... So I used Disk Utility to free up some space from the OS X partition, and upon restarting to Windows in order to add the free space to windows, I discovered that windows no longer boots! OS X still boots, but how can I fix my Windows partition without reinstalling Windows and losing all my data?
The following worked for me.  I have macOS 10.12.3 and Windows 10.


Boot to Recovery mode (restart, hold "command+R")
Utilities -> terminal
Run 

fdisk -e /dev/disk0"
p
setpid 4
[press enter]
flag 4
p
write
y

Reboot