MacBook will only boot into Windows; can only use external display

Thanks, Loner. Held Command+R for about 10-15 seconds of blank screen and then got a Mac startup screen with the progress bar at zero. That lasted about 1-2 seconds before the gray screen of death appeared. I tried Command-Opt-R as well. That one didn't have any effect -- it just booted into Windows.

Incidentally, I also found the "Recovery" settings in Windows, and I was able to select "Mac OS" as the boot drive there. However, it didn't make any difference. Still booted into Windows.

Windows Automatic Updates are enabled. In fact, it just completed another update.

BTW, I also tried the screen brightness buttons. Unbelievably, I hadn't thought of that before, so thank you for reminding me! Unfortunately, however, it didn't work.

I tried to back up at least the Windows data, but of course the MacBook only has one port. That port is being used by the monitor. I tried using my dongle adapter to connect a USB drive and the monitor -- something I have routinely done while in Mac OS -- but at least while using Windows, the machine fails to drive the display through the dongle. Since the built-in screen is not working, this means I cannot see what is going on to do the backup. I have also thought about putting it into Target Disk mode (if that even still exists), but of course I have no way to connect the MacBook to my 2013 MacBook Pro to do this. I knew that the limitations of the single USB-C port would be annoying when I bought the machine, but I thought that I could work around them, and I never anticipated just how frustrating they would actually be.

Anyway, at this point, I'm thinking that this calls for a visit to the local Apple Store.

Hi Loner, thanks again for the quick response!

I don't have the requisite cables for TDM, although I do have USB-C to TB(?). I don't have a USB-C monitor. I'm using a 24" LED Cinema Display.

I will try those procedures and report back in an hour or so.

Hi Loner, I tried the procedure to reset the SMC. Unfortunately, now it will not chime or start up in either OS. It seems to be completely dead. I've made an appointment at the Apple Store for tomorrow. Thank goodness for AppleCare!

Thanks so much for your prompt responses and all your suggestions. I will let you know how the visit to the Store goes.

Best,

Tyson

Hi Loner, OS X is still dead. I did try changing the settings in Windows' Control Panel, but it didn't work. It was set to mirror the displays, and I tried to set the displays to show a single, extended desktop. It seemed like it tried to comply, but then the setting reverted back to mirrored. It seemed like it was unable to communicate with the built-in display.

So my wife took the machine to the Apple Store yesterday. Somehow they were able to get MacOS back up and running. However, the built-in display was still dead, so they sent it back to Apple for hardware repair. Covered by AppleCare, of course.

Hi Loner, I tried it again and managed to get Windows back. But still back to the original problem. Will let you know how things go at the Store today.