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 all you to erace your externa; drive and ass a new partition.
Fix 3:- (for Windows users)
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 “disport” 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.
- Type “select disk 1” (use the disk number instead of 1), click Enter.
- 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. This command start formatting your device.
Also try to format your external hard drive with Disk Utility.
If you knew any other solutions, do let us via comment.