I upgraded from yosemite to sierra and now can no longer use my win 10 bootcamp partition. In Sierra I can mount it and view the files but holding option at startup no longer gives me the option to boot into windows. If I change startup disk to windows I get "no bootable volume" booting into recovery and running disk util verifies fine and repairs fine.
HEEEEELLLLLLLLPPPPPPPP!!!!!!!!!
HEEEEELLLLLLLLPPPPPPPP!!!!!!!!!