Want to install Neon on my new external SSD.
I have splitted it in half with two partitions, the first NTFS for my Win 11 usage (where I have already installed different programs), the second in ext4 for Neon and Linux usage.


But the Neon installer (booting from a live disk) is seeing only a single unpartitioned volume, so that I cannot proceed with the installation without deleting the already created NTFS partition. KDE Partition manager show also a single unallocated partition.

Are you sure your selecting the correct disk?

I just played with the installer and it shows three options, overwrite existing partition, overwrite the drive or manual partition. That is with a drive already partitioned.

There no such thing as an unallocated partition, just unallocated or free drive space...

What software did you use to create the ext4 partition for Neon?
Did you install windows 11 in UEFI mode?

You say in the next sentence there is only a single unallocated "partition", so which is it, an ntfs partition you see or unallocated space? Have you tested booting windows 11, all works? Without more information, I'd have to agree that it seems you are looking at the wrong drive. Can you post the outpt of "sudo fdisk -l" or "sudo parted -l"?

I used Paragon Drive to create and format the partitions.
The NTFS it's not a primary just an extended partition with no Windows, is used just as an extended space to install programs I'm using rarely.
Curiosly Dolphin is seeing both partitions correctly.
In partition manager and Neon installer on the contrary is shown as unallocated space.
Didn't have access to my pc right now can post more info later if needed.

It maybe an installer bug. Post exactly how the drive is partitioned.

sudo fdisk -l
or
lsblk

The disk I want to install Neon on is sda2.

This is what is shown on the installer selecting sda (Neon 5.23 user edition)
https://i.imgur.com/sErSctT.png

Boot into the neon instller, what is the output of If the output is "it is a directory" you will need to either use manual partitioning or convert sda to a gpt drive.

From the posted screenshot the installer does not recognize the partition table. You can see the ? to the right of the drive box.

While not a direct comparison since I created the partitions using fdisk while running Neon from within a VirtualBox guest using both efi and legacy modes. The options are different but the partitions are recognized correctly. The difficult part is why.

Attached Thumbnails

   

cat /sys/firmware/efi output it's a directory.
Converting sda from msdos to gpt is meaning loosing all my data?
sda1/sda5 (didn't understand why show two partitions if there is only one) are already with many Win applications installed and if possibile I would like to don't need to re-install all from scratch another time.

Just a remark: the disk is installed in an eGPU box (CoolerMaster Mastercase EG200), connected trough Thunderbolt to my laptop. I'm seeing the disk without any problem both on Win and Linux so I suppose this didn't play a role, but pointg out in case I'm wrong.

You have windows installed with efi booting on the drive nvme0n1 (nvme0n1p1 is the efi partition)
It appears you have really messed up the partitioning on /dev/sda.
Your output of 'parted -l' shows which shows that you created an msdos partition table. /dev/sda1 looks like you intended a second efi partition (which is not necessary) and that the start/end sectors for each partition show overlapping.

I think your only chance for recovery may be to backup the data on the ntfs partition then repartition /dev/sda as gpt before you install.

From this output it shows additional confusion which is not understood by linux
I don't even understand that because it shows the extended and logical partitions before the primary partition which should not happen.

Technically there isn't any reason a primary has to be the first partition. Well an extended is a primary but you know what I mean, the order does not matter and linux can boot from either. In the distant past with the 1024 cylinder limit that might of been the case but not now.

The OP has two problems, why the Neon installer is not recognizing the partition table and that they need to convert the drive to gpt. It might be due to the eGPU box but if that was the case I would of expected fdisk or parted to not recognize the table either. Its probably easier to just backup the drive and start from scratch versus trying to convert the drive in place.

Another thought, was the windows partition shutdown in hibernation mode?

Friday I have a demo where I need to use the eGPU and his attached SSD with the Windows partition where I have installed the specific programs I need to use.

After that I will clean all, recreate the partitions using GPT and let's see if this will work.

I love Neon and tried (without being able to) switch to Linux as my main drive, but in the end this is the reason I suppose will be never a for all OS: you need above the average knowledge to get even the basic things. But I suppose this is the strenght and weakness of an ever evolving complex system.

The most beautiful thing is anyway his wonderful and supportive community, that saved me so many times.

Only yesterday I was finally able to try the MBR-->GPT path, and it worked, just needed to backup my Windows partition files and re-copy them in place once finished and all is working again, on the Linux side I was able to select the ext4 partition and install Neon.

But: after a first Neon upgrade I got notification a second update was needed, with just a 2MB Intel Management something and 300k of 2 Neon files to upgrade. The system rebooted, but asked a second time for the same upgrade and at the second reboot I become stuck in the grub cli as in this screenshot

https://imgur.com/gallery/FvYWXpb

Curiosly even before resetting everything I come to this screen every time I booted my laptop, I supposed the reason was since in BIOS there is an old ubuntu entry from a previous test using the same eGPU setup and the eGPU it's not always connected (so that the disk attached to the eGPU box was not found).
But now even with the eGPU connected I got this grub cli screen and didn't know what else to do, except use Alt+Ctrl+Del to reboot.

Next the various info about the disks (booted from usb key live image)