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How To Fix “Cannot Create a Partition Table on /dev/sdb” Error in Ubuntu

Ubuntu 13

Ubuntu, a popular Linux distribution, is known for its robustness and versatility. However, like any operating system, it can sometimes throw errors that can be challenging to troubleshoot. One such error is “Cannot Create a Partition Table on /dev/sdb”. This error typically indicates that Ubuntu is unable to read or write to a specific drive, in this case, /dev/sdb. This article will guide you through several possible solutions to resolve this issue.

Checking the Device Name

The first step in troubleshooting this error is to verify that the device name is correct. In Linux, devices are often named in the format of /dev/sdX, where X is a letter that varies depending on the number of drives connected to your system.

You can use the fdisk command to list all available devices:

sudo fdisk -l

This command will display a list of all drives and their partitions. Look for your SD card in this list and verify that it is indeed /dev/sdb.

Reconnecting the Drive

Sometimes, a simple disconnect and reconnect can resolve connection issues. Unplug your SD card from your computer, wait a few seconds, and then plug it back in. Once it’s reconnected, try creating the partition table again.

Checking System Log with dmesg

The dmesg command is a powerful tool that can provide more information about the cause of the I/O error. It displays the system log, which includes messages from the kernel that can help diagnose hardware issues.

Run the following command:


Look for any error messages related to /dev/sdb. These messages can provide clues about what’s causing the error.

Testing the SD Card on Another System

If the error persists, try using the SD card on a different computer or operating system. If the SD card works on another system, the issue is likely specific to your Ubuntu installation. If the SD card doesn’t work on another system, it’s likely that the SD card itself is faulty.

Backing Up and Replacing the SD Card

If none of the above solutions work, your SD card may be damaged. Before replacing it, make sure to back up any important data. You can use the dd command to create a backup image of the SD card:

sudo dd if=/dev/sdb of=~/sdcard_backup.img bs=4M

In this command, if=/dev/sdb specifies the input file (i.e., the SD card), of=~/sdcard_backup.img specifies the output file (i.e., the backup image), and bs=4M specifies the block size.

After backing up your data, you can replace the SD card. Once you have a new SD card, you can restore your data using the dd command:

sudo dd if=~/sdcard_backup.img of=/dev/sdb bs=4M

In conclusion, while the “Cannot Create a Partition Table on /dev/sdb” error can be frustrating, it’s usually possible to resolve it by following the troubleshooting steps outlined in this article. Remember to always back up important data before making any changes to your drives. If you need further assistance, don’t hesitate to seek help from the Ubuntu community.

What should I do if the `fdisk` command does not display my SD card?

If the fdisk command does not display your SD card, it is possible that the card is not being recognized by your system. Try reconnecting the SD card, ensuring it is properly inserted into the card reader or slot. If the issue persists, try using a different card reader or USB port. You can also try using the lsblk command to list all available block devices and check if your SD card is listed.

How can I safely disconnect my SD card from the computer?

To safely disconnect your SD card, make sure you unmount it first. You can do this by right-clicking on the SD card icon on your desktop or file manager and selecting "Unmount" or "Eject". Wait until the SD card is no longer in use (you may see a notification indicating it’s safe to remove), then physically remove the card from the card reader or slot.

Can I use the `dd` command to create a backup of my SD card on Windows?

The dd command is a Linux command and may not be available on Windows. However, there are alternative methods to create a backup of your SD card on Windows. You can use third-party software like Win32 Disk Imager or Rufus to create an image of your SD card. These tools provide similar functionality to the dd command and allow you to create a backup image of your SD card.

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