How to Clean USB Pendrive with installed ubuntu gnome 16.4 encrypted (with passphrase) that wont mount

Question

I installed Ubuntu Gnome 16.10 or 16.4 on usb PQI MINI with 16GB, encrypted with and I have passphrase. But after few launches it crashed, but I liked Ubuntu and installed on ssd. But when I want to clean my PQI MINI from old system I cant even mount it...

Here are some checks:

sudo dmesg | tail -20

[116206.287030] usb 2-1.2: usbfs: process 5543 (ThreadWeaver::T) did not claim interface 0 before use
[116206.368385] usb 2-1.2: reset high-speed USB device number 4 using ehci-pci
[116206.572295] usb 2-1.2: reset high-speed USB device number 4 using ehci-pci
[116206.690825] usb 2-1.2: usbfs: process 5543 (ThreadWeaver::T) did not claim interface 0 before use
[116206.772265] usb 2-1.2: reset high-speed USB device number 4 using ehci-pci
[116206.886786] usb 2-1.2: usbfs: process 5548 (ThreadWeaver::T) did not claim interface 0 before use
[116206.886831] usb 2-1.2: usbfs: process 14167 (pool) did not claim interface 0 before use
[116206.886851] usb 2-1.2: usbfs: process 5549 (ThreadWeaver::T) did not claim interface 0 before use
[116206.886887] usb 2-1.2: usbfs: process 14167 (pool) did not claim interface 0 before use
[116206.886891] usb 2-1.2: usbfs: process 5549 (ThreadWeaver::T) did not claim interface 0 before use
[116206.886925] usb 2-1.2: usbfs: process 5543 (ThreadWeaver::T) did not claim interface 0 before use
[116206.887053] usb 2-1.2: usbfs: process 5549 (ThreadWeaver::T) did not claim interface 0 before use
[116206.887058] usb 2-1.2: usbfs: process 14167 (pool) did not claim interface 0 before use
[116206.887092] usb 2-1.2: usbfs: process 5543 (ThreadWeaver::T) did not claim interface 0 before use
[116206.887174] usb 2-1.2: usbfs: process 5544 (ThreadWeaver::T) did not claim interface 0 before use
[116206.887484] usb 2-1.2: usbfs: process 5544 (ThreadWeaver::T) did not claim interface 0 before use
[116347.916252] EXT4-fs (sdc1): INFO: recovery required on readonly filesystem
[116347.916254] EXT4-fs (sdc1): write access unavailable, cannot proceed
[116372.971725] signonpluginpro[14581]: segfault at 7fddeeafbb98 ip 00007fdde89bc5df sp 00007ffcf7c3d490 error 4 in

libQt5Network.so.5.6.1[7fdde8926000+16e000] [116469.963898] signonpluginpro[14919]: segfault at 7f0ac25e3b98 ip 00007f0abc4a45df sp 00007ffd45bf2e70 error 4 in libQt5Network.so.5.6.1[7f0abc40e000+16e000]

sudo fdisk -l

Disk /dev/sdc: 14.5 GiB, 15504900096 bytes, 30283008 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xa597e4f9

Device Boot Start End Sectors Size Id Type /dev/sdc1 *
2048 30281727 30279680 14.4G 83 Linux

What should I do? Also I tried to mount it with commands that I found in the web. When in gnome-disks I click mount, it wont mount (with default settings).

Answer 1

Have you tried dd? mkusb puts a layer of safety around dd. You can use it to fill the disk with 0's, making it possible to format in Windows or Linux. This may not work if there is physical damage.

Answer 2

When a USB pendrive behaves like this:

sudo dd if=/dev/zero of=/dev/sdc bs=1M dd: failed to open '/dev/sdc': Read-only file system

I think that something is wrong with the internal hardware or software of the pendrive. This condition is sometimes referred to as 'gridlocked'. A mass storage device /dev/sdx should not be read-only for the superuser (sudo). This is independent of the content of it (whatever is written into it).

But let us hope, that it is a mismatch between the pendrive and your computer (hardware or software) or a particular USB port! Maybe it works 'somewhere else'. It is a good idea to

• reboot and test again
• test in another USB port
• test in another computer
• test with another operating system.

For example, you can try to format the pendrive with Windows. Ask some friend or colleague to try in their computer.

Finally, are you sure that you have not set it read-only by mistake with a micro-switch on the pendrive? Things like that can happen to linux gurus too, so have a second look at it ;-)

Answer 3

• On some pendrives there is a small mechanical switch for write protection, that can toggle between read/write and read-only. You might have set it read-only without intention.

• Reboot the computer and try again with dd or safer with mkusb again.

• Try other USB ports and another computer.

If still no luck, the USB drive is probably 'gridlocked'. See this link and links from it.