I want to format my USB drive. In terminal, I use the following commands:

umount /dev/sdb1
mkfs.vfat -I -n "New Volume" "/dev/sdb1"

But I could not. It shows me following error:

mkfs.vfat 3.0.12 (29 Oct 2011) 
/dev/sdb1: Permission denied

Somebody helps me, please. Thank you in advanced.

Ps: When I add sudo before the above commands, it works. But nothing changes. My old files and folders still remain. Gparted also does not work. It shows me the following error:

enter image description here

When I try to format by Disk Utility, it shows me the following error: Error formatting volume Error creating file system: helper exited with exit code 1: Error calling fsync(2) on /dev/sdb1: Input/output error

  • Did you run above commands with sudo or without sudo?
    – d a i s y
    Feb 29, 2016 at 3:56
  • I have updated the instructions
    – mchid
    Feb 29, 2016 at 4:33
  • In order to see the "details" you have to expand the menu for format.
    – mchid
    Feb 29, 2016 at 4:41
  • It shows nothing.
    – Truong
    Feb 29, 2016 at 4:41
  • 1
    I edited the picture.
    – Truong
    Feb 29, 2016 at 4:53

1 Answer 1


That Input/Output error message suggests there are hardware problems (not viruses as your comments that exist on a now-deleted answer say you think is the case).

You say in those now-deleted comments that Windows also says it can't write to the drive. This further suggests a hardware issue with the USB drive specifically.

It is almost a guarantee that this is a hardware issue, since every attempt to edit the file system (based on your comments) on any operating system results in that error or similar.

I would surmise that your USB drive is no longer functional as a usable USB stick and likely will end up not functioning at all soon enough; I would back up any data you wish to keep and replace the drive as soon as possible to prevent data loss.

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