Apple - Unable to find driver for this platform \"ACPI\" MACOSX version: not yet set

Try starting up from the recovery partition (by holding command-R), in single user mode (by holding command-S), in safe mode (by holding shift), or in Internet recovery mode (by holding option-command-R).

If you already have backups and you can start up from the recovery partition or in Internet recovery mode, try choosing the Reinstall OS X option. It downloads an OS X installer and installs it over the current installation, keeping user files and settings in place.

If you can start up from the recovery partition but reinstalling OS X does not work, try to erase and reinstall OS X.

If you don't have backups but you can start up from the recovery partition, you can save a disk image to an external drive with Disk Utility.

This happened to me today too, on a Mac Mini Late 2013. I have many partitions on the only internal hard drive, with a multiboot configuration with macOS 10.9, 10.10, 10.11, 10.12, 10.13. I suspect this problem has been caused by the update of macOS 10.13.4 to 10.13.6

However, this is how I fixed it:

1. Boot into Recovery Mode:
   • Start the Mac, and as soon as you hear the boot sound, press and hold pressed Option, until you see the boot menu appearing
   • Select the disk named Recovery-10.9.5 (or whatever macOS version you have)

2. Update the Kernel Extension cache:

   • Start the Terminal (you can find it in the Utilities menu)
   • Identify the correct volume by typing

     mount

     on the command-line
   • Find the right volume in the list, for me it was:

     /dev/disk0s2 on /Volumes/Mavericks (hfs, local, journaled)

   • Change directory to the volume root by typing

     cd /Volumes/Mavericks

   • Rebuild the kext cache by typing

     touch System/Library/Extensions
     kextcache -f -update-volume ./

3. Reboot your Mac and voilà! Problem fixed!