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Question: gparted keeps claiming "The backup GPT table is corrupt, but the primary appears OK, so that will be used.". It persists even when I wipe the GPT table using gdisk, try to create new gpt table, try to create new mbr table.

Background: Recently, I got a new SSD drive. I used clonezilla to copy my old Ubuntu installation from a smaller SSD over to it, and it worked fine. Then I installed Windows on the side. There were some problems, but each system booted correctly more or less half of the time, but at some point, I could no longer boot Ubuntu at all.

I booted into a live usb, and in there, gparted and parted both gave me a message:

The driver descriptor says the physical block size is 2048 bytes, but Linux says it is 512 bytes

I thought maybe clonezilla did something wrong in the new ssd, so I turned off the computer, unplugged the new SSD and left an old HDD plugged in. To my surprise, I got the same message from gparted after rebooting, so I decided to use the HDD as a test ground for solutions. There were some similar posts here and elsewhere -- only they were for usb sticks -- and according to the answers given there, I backed up all the data from the HDD to an external drive (this time without any low-level tools, just nautilus), and erased the whole disk via dd if=/dev/zero of=/dev/sda bs=100M.

When it finished, I no longer got the message. However, parted threw at me

The backup GPT table is corrupt, but the primary appears OK, so that will be used.

I tried to create new partition table (gpt and msdos both), create new partitions, tried zapping everything with sgdisk -Z /dev/sda, overwriting the gpt via gdisk, tried installing windows and linux on top of the zapped gpt, and the problem persists. Installed Linux boots up fine. I did not try to boot Windows (I did not go past partitioning phase, I just wanted it to create new partition table with its own tools). Except for the gparted alert, there does not seem to be anything overtly wrong, but I'm worried that if I just ignore it, it will not only be annoying, but also lead to some more problems downhill.

I feel entirely helpless at this point. I have no idea what the problem might be. Unfortunately, I don't have any other device at hand to check the disks (though if all else fails, I suppose I'll try that).

tomasz
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2 Answers2

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Actually, it turned out that the problem with GPT table was not on the hard drive I had nuked, but the very pendrive I used for rescue. Furthermore, it seems like the initial problem was not at all present on the ssd, and I am not sure if it was even present on the hard disk. Long story short, I very much do not recommend using rufus for making live usb.

The source of my confusion (in both cases) is that gparted didn't tell me which drive it had problems with.

For future reference, if anyone has a problem like this, you can do the following:

  1. Start parted (the terminal version).
  2. Type select /dev/sdX to select the device in question.
  3. Type print (not print all). Then it will tell you if it thinks something is wrong with the device you have selected.
tomasz
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You can tell which drive GParted is having problems with: when the error comes up, you can see, behind the popup error message, that in the GParted status bar, at the bottom left corner of the GParted window, the message "Searching /dev/sdb partitions," where /dev/sdb will be replaced with whatever device is applicable in your situation.

Thomas Hansen
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