' Hi there, do you know how to make the external hard drive accessible again when it shows as 'Read Only' on Mac? I'm having this problem that my Seagate hard drive suddenly turned to read-only this morning when I connected it to Mac. The External Hard Drive Shows Up as 'Read Only' on Mac, Help! Open Disk Utility > Select the external hard drive and click 'First Aid' > Click 'Run'. Right-click external drive > 'Get Info' > 'Sharing & Permissions' > Check 'Ignore ownership on.'. Open 'Applications' > 'Utilities' > Launch 'Disk Utility' to 'Erase' external drive > Restore formatted data.