Apple released its latest macOS update in September, dubbed High Sierra. For most, it should provide a fairly solid experience, however, if you want to perform more advanced tasks, such as formatting an unformatted disk, you might run into a problem. By default, the Disk Utility application doesn’t appear to be listing raw disks which are plugged in, but there is a way to fix this.
Tinyapps reported the weird bug in a blog post, saying:
“macOS 10.13’s Disk Utility 17.0 (1626) does not recognise raw drives. Here is an example while booted from the installer, attempting to prepare a new internal drive [image of Disk Utility not displaying unformatted drive] … However, as seen in the blue Terminal window, diskutil does recognise the drive. We’ll use it to perform a quick, cursory format to make the disk appear in Disk Utility, where further modifications can easily be made.”
Tinyapps demonstrated that inserting an unformatted drive is noticed by the system and then a dialogue box is presented asking the user whether they want to initialize, ignore, or eject the disk; initialising the disk opens Disk Utility, where the unformatted disk isn’t visible.
If you find yourself in this predicament it can be fixed by going into the Disk Utility, pressing View > Show All Devices, then quitting the program and relaunching it – following this process, you should see the disk. If for some reason this doesn’t work then you may have to work out the 'diskutil' Terminal command.