unless you click View > Show All Devices, quit Disk Utility, then relaunch it (thanks to xenadu02 for the workaround!)
Update: This issue appears to be resolved in macOS 10.13.3 / Disk Utility 17.0 (1635)
macOS 10.13's Disk Utility 17.0 (1626) does not recognize raw drives. Here is an example while booted from the installer, attempting to prepare a new internal drive:
However, as seen in the blue Terminal window, diskutil does recognize the drive. We'll use it to perform a quick, cursory format (e.g., diskutil eraseDisk JHFS+ NewDisk GPT disk0) to make the disk appear in Disk Utility, where further modifications can more easily be made:
Plugging in an unformatted external drive produces the usual alert, "The disk you inserted was not readable by this computer. Initialize... | Ignore | Eject", but clicking Initialize just opens Disk Utility without the disk appearing:
As shown above, clicking View > Show All Devices does not cause the raw disk to appear.
UPDATE: Fans of Disk Utility's last classic version (13 (606) from OS X 10.10 Yosemite) have got it running in El Capitan and Sierra:
Disk Utility version 13 was the last to support:
However, in light of APFS and other changes, it may be wiser to simply use diskutil and hdiutil instead.
/mac | Oct 01, 2017