I am unable to create an extended partition on my disk in Gparted: the option is greyed out! I resized the primary partition on the disk to leave some unallocated space, and I wanted to make the extended partition there so I could make 3 logical partitions in there, but I can't.

I do not have any other extended partitions on the disk; the only other partition is the primary partition which I do not want to lose data from.

As you can see in this screenshot, the "Extended Partition" option is greyed out and cannot be selected.


Any help would be appreciated here! I apologise for the small text, it is because my laptop has a 1080p resolution, so the system is scaled for that.

EDIT 1: I believe the partition table is msdos (not 100% certain), I can only have 2 primary partitions maximum...

EDIT 2: Output of sudo fdisk -l /dev/sdb:

ubuntu@ubuntu:~$ sudo fdisk -l /dev/sdb
Disk /dev/sdb: 114.6 GiB, 123010547712 bytes, 240254976 sectors
Disk model: Ultra Fit       
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: 0x73736572

Device     Boot      Start        End    Sectors   Size Id Type
/dev/sdb1       1920221984 3736432267 1816210284   866G 72 unknown
/dev/sdb2       1936028192 3889681299 1953653108 931.6G 6c unknown
/dev/sdb3                0          0          0     0B  0 Empty
/dev/sdb4         27722122   27722568        447 223.5K  0 Empty

Partition table entries are not in disk order.

(By the way, in this state there is only the 1 partition on the disk which is NTFS)

  • what kind of partition table is it? msdos? or gpt? gpt only has "primary" partitions, but as many as you want (not the limit of 4 in msdos partition tables -- extended partitions are a hack to get around that limitation).
    – cas
    Sep 29 '19 at 9:20
  • @cas - I believe msdos - I can only create 2 primary partitions
    – Daniel M.
    Sep 29 '19 at 10:07
  • can you edit your question and post the output of sudo fdisk -l /dev/sdb? (not in a comment, that makes for an unreadable mess).
    – cas
    Sep 29 '19 at 11:14
  • 2
    If I were to guess, I'd say there is no partition table, because the "partition" is named /dev/sdb. What does it show if you enable "View -> Device Information" in the menu?
    – Freddy
    Sep 29 '19 at 11:19
  • 4
    You actually have a file-system on your device /dev/sdb. You do not even have a partition table and therefore cannot have partitions. @Freddy's comment should be the answer.
    – Hermann
    Sep 29 '19 at 14:02

Like @Freddy stated in the comments, it seems there was no partition table at all on this disk. I have resolved this now by creating a partition table on the disk. Thanks for all your help anyway!

  • Solved for me the problem! It appears that if you have installed a live-iso to an ssd (or usb), this is done without a partition table. So in case you want to delete this partition , you have to create the partition table again before adding new partitions Dec 31 '20 at 9:14

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