NEED HELP: Installed Boot Camp and can no longer boot to Mac OS

[ducatiti]

So I installed Win 10 via Boot Camp on my 2017 MBP 15". Installed all the updates on the Mac prior to installing and on Windows upon installing, both Apple and Win updates.

Tried to select Mac OS as a target for the next boot up, but an error popped that it could not be found. In the My Computer (thingy, pardon my Windows lingo as I have not touched Windows since Win7), Macintosh HD is not shown but rather just the Boot Camp Partition. Upon installing Windows, it didn't even prompt me to what partition to install Win so I didn't have to format anything. All I did was select 100GB for the Boot Camp partition and let the system do the rest. Now I'm screwed. Every time I restart, it goes straight to Windows not even a chance to press option to select what drive to use to boot up.

Edit: As I am typing this, I tried to plug in a usb High Sierra install disk and selected it on Windows to restart to boot. I was able to get to Disk Utility and see the physical disks, both Macintosh HD and Boot Camp.

Please help me. Is there an easy fix for this?

Thank you in advance.

 

[SteveJUAE]

Holding down the Option key during startup will show you a boot screen with all bootable devices listed. You can use the mouse or the keyboard to select a device to boot into.

You can then check bootcamp manger in both to check options you may need to reinstall the W10 Boot Camp utilities from the USB stick

 

[CWallace]

This caught me out today, as well (I just updated to High Sierra).

The current Boot Camp drivers cannot read APFS volumes so once you upgrade to High Sierra, your macOS volume becomes invisible to Windows / Boot Camp.

Until Apple updates the Boot Camp files to read APFS, you will need to follow SteveJUAE's instructions of holding down the Option Key during the boot process to select the macOS volume (you can then set the macOS volume back to the default boot device via Settings -> Startup Disk).