Unable to format USB: mkfs.vfat: unable to discover size of

Question

This question is not a duplicate. I followed the thread showing how to format usb but it didn't help (see below for details). Please also read the comments section

I tried to follow How to format a USB stick thread to format my USB drive. However, sudo mkfs.vfat /dev/sdb1 still produces the following error.

mkfs.fat 4.1 (2017-01-24)
mkfs.vfat: unable to discover size of /dev/sdb1

The size of USB pendrive seems to be incorrect:

$ lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
--truncated--
sdb      8:16   1   7.2G  0 disk 
└─sdb1   8:17   1   239M  0 part

As you can see, the USB has size of 7,2G but there is one partition of size 239M.

I also tried wipefs -a /dev/sdb to erase all the partitions in USB thumb. Still, no luck.

Neither sudo dd if=/dev/zero of=/dev/sdb bs=512 count=1 or sudo dd if=/dev/zero of=/dev/sdb bs=512 has worked as I'm still getting mkfs.vfat: unable to discover size of /dev/sdb1.

You create partitions first then you place a filesystem on the created partitions! your going about it the wrong way! — George Udosen, Dec 22 '18 at 14:24
@GeorgeUdosen Could you write in what order I should approach this, please? — menteith, Dec 22 '18 at 14:27
It is not duplicate. I did what the above thread suggested, but without luck. — menteith, Dec 22 '18 at 14:28
Wipe the usb with dd then use fdisk to place a partition on it with the whole disk as the size. After place a filesystem on it with mkfs.vfat... — George Udosen, Dec 22 '18 at 14:30
Not a duplicate. My drive was 7,2GB and still is: sdb 8:16 1 7.2G 0 disk. Please do read carefully. — menteith, Dec 22 '18 at 15:09
using gparted or something, you should try creating new partition table and then format — Alex Jones, Dec 22 '18 at 16:57

score 0 · Answer 1 · edited Jun 12 '20 at 14:37

Probably your partition table is corrupted. The easy way to move forward is to open gparted and and in the top right go to /dev/XdYand select the disk you want to edit:

This will destroy everything on the USB stick!

Go to the menu Device
Then Create Partition Table
Then msdos
Press OK

Now you can create new partitions the way you want them...

If the above fails: Your USB stick is toast! Throw it away and buy a new one!

Unable to format USB: mkfs.vfat: unable to discover size of

1 Answers1

This will destroy everything on the USB stick!