Mar 25, 2018 I have recently bought a “My Passport” External HD. And, I am a Mac User. Running Mac OS X 10.6.8. Where and with working to reformat my new HD, I have been directed to base “Support” and then 'Knowledge Base Answer ID 3865. Where, I am seeing “Instruction” links, for Mac Operating System, for as far back as Mac OS X 10.7. Make sure you tick the checkboxes “Hard Disks” and “External Disks.”. Your WD My Mac Passport drive should now be running on your screen. Launch Disk Utility. You can find disk utility by clicking on the spotlight search button, then type “Disk Utility”. Highlight “Disk Utility”, then double-click it. Make sure you tick the checkboxes “Hard Disks” and “External Disks.”. Your WD My Mac Passport drive should now be running on your screen. Launch Disk Utility. You can find disk utility by clicking on the spotlight search button, then type “Disk Utility”. Highlight “Disk Utility”, then double-click it.