I created and used a Windows 10 Bootcamp partition on my retina MBP 2013 running MacOS 10.12.2 about a month ago. I recently returned from a three week trip (I left my laptop at home) and installed MacOS 10.12.4 beta (16E163f) on my laptop. I am now unable to boot into Windows. When I held the option key during startup, the only thing that appeared was the Macintosh HD partition.
I booted into Mac and checked that the Bootcamp partition mounted successfully. It did. I went to System preferences and clicked on the Startup disk preference panel. My options were Macintosh (indicated by the drive icon and Windows (indicated by the folder with the Windows icon on it, like usual). I clicked on the Windows folder and hit the restart button. When the computer booted up, it showed a black screen with white letters reading "No bootable device -- insert boot disk and press any key".
I never installed MacOS 10.12.3 on this computer (I skipped from 10.12.2 to 10.12.4 beta).
UPDATE: Bootcamp partition still doesn't work on newest beta (release 4, build 16E175b).
My questions are:
What could have caused this problem? The partition was fine a month ago.
Has anyone else seen this problem and, if so, what have you done to fix it?
Even if you haven't seen this problem, what should I do to continue to try to troubleshoot this problem? Can I fix the boot error without losing my Bootcamp partition? (I have a backup as a disk image. Please note that I would like to avoid reinstalling the 10.12.3 OS release if possible, but if that's the only idea I can try that too.)