When Mac users try to format an external hard drive like seagate SSD, Samsung SSD or flash drive using terminal diskutil command it shows error message like “Error: -69760: Disk erase failed with the error Unable to write to the last block of the device”.
- Connect your external USB disk into a Linux box or Ubuntu and partition it.
- Then plug the disk back into the Mac. You can format the Linux created partition with Journaled HFS+.
Fix 2 :-
Try to use 3rd party partition manager apps like GPARTED Live or iPartition apps. These apps will erase your externa; drive and as a new partition.
Fix 3:- (For Windows users/PC)
You can fix a corrupted USB in Windows 7 or 8.
- Click the start button.
- Type and Enter “cmd” in search field.
- In command window type “diskpart” and click Enter button.
- Then type “list disk” and click Enter.
- Note the disk number associated and note the space that best matches your USB space.
- Next type “select disk 1” (use the disk number instead of 1), click Enter.
- After that type “clean” and click Enter.
- Type “create partition primary” and click Enter.
- Type “active” and click Enter.
- Type “select partition 1” and click Enter.
- Type “format fs=fat32” and click Enter. Now this command start formatting your device.
- Restart your mac from Apple menu, and reboot in recovery mode. Then reformat the external drive using disk utility from the recovery partition. It worked like a charm!
- Run disk utility from the recovery partition. And format drive in normal would and boot it.
Also try to format your external hard drive with Disk Utility.
Guys I hope this will work you to solve the problem. And if you have any other solutions, let’s me know in the comment section below.