Had this happen a couple times now. Working with Windows 10 and Ubuntu and occasional re-use disk from one machine to the other. Had a working boot disk that suddenly stopped after a couple weeks and when I looked at it in Disks, it showed twice the size and had Windows and Linux partitions neither of which were accessible. The screen shot attached shows the same problem on a different disk. The partition 1 contains a couple thousand files I'd like to have back. I was able to recover some, but they are incomplete and the recover process did not recover the file names. Less important than recovering the data is figuring out why formatting the disc is not removing the old partitions. Working with Ubuntu 20. I am pretty sure I formatted the disk and then created an ext4 partition, but it is showing here as a windows format. Thanks enter image description here

  • Partition 1 is an extended partition. It contains nothing but logical partitions inside. There's no "Windows partition" shown in the screenshot. So this question apparently stems from misunderstanding what an extended partition is. Jun 7, 2021 at 23:27
  • While that is interesting, it does nothing to answer my question. Let me restate. I do not know why this happened. Clearly that is not a normal representation of partitions on a disc. Do you know what would have caused it?
    – Loffler
    Jun 8, 2021 at 0:45
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    Clearly that IS a completely normal-looking representation of an old disk with one primary partition and one extended partition. There is no useful data in your screenshot suggesting why your ext4 partition does not exist here. Maybe you erroneously partitioned a different disk. Maybe you did not commit the partition change. Lots of possible maybes. Try re-partitioning again. If the disk refuses to re-partition, or is otherwise unreliable, then replace it.
    – user535733
    Jun 8, 2021 at 1:05
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    The problem is that you have a MBR partition table on a 6TB disk. It should be GPT/GUID.
    – heynnema
    Jun 8, 2021 at 2:03
  • It was a data disk on a stable system. No disk changes were being made. Certainly did not create 4tb of partitions on a 3tb disk. This has happened twice so I was hoping there was a known cause. Maybe it is just a disc failure.
    – Loffler
    Jun 8, 2021 at 2:08

1 Answer 1


As the previous posters noted, this was a user error. Hard drive was originally connected to a Windows computer and when I moved it to ubuntu, I did not delete the original partitions. Among other problems, I thought it was a 3tb drive instead of a 6tb (when I put in the linux box the Disks app showed 3tb free).

To fix the problem I used fdisk from the command line to find the drive and gdisk to remove all the partitons. Then created a GPT table and formatted the new partition.

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