24.04 installer creates a new undesired partition

Hi all, I have a desktop with a nvme disk of 1 TB. The disk has 10 partitions (see gparted attached). One partition is named sys1 and is my actual ubuntu mate 22.04 working partition, another partition is named sys2 (nvme0n1p3) that is the partition where I want to install 24.04 in order to try and tune-up before switching there my working partition. I've made this procedure at every upgrade.
I downloaded 24.04 installer from Mate download page, I created a bootable USB and then I tried to install. The installer asks me if I want to install 24.04 beside Mate 22.04, I say yes. Then asks me the partition where to install, I say nvme0n1p3 (see image attached).
At the end, in the resume I see that it is going to create a new partition nvme0n1p11 (see image attached). Why?
I don't want a new partition.
Any workaround to install everything in the partition I want?
Thx a lot for your help.

Hi, @smurf!

No, it asks you about installing Ubuntu MATE 24.04 alongside regular Ubuntu 22.04. It thinks Ubuntu 22.04 is already installed on your p3. Then it tries to split your p3 into two partitions:

  1. shrink p3 to 2.6 GB to keep regular Ubuntu 22.04;
  2. create p11 sized 34.3 GB to install Ubuntu MATE 24.04.

You probably previously had some regular Ubuntu 22.04 installed on your p3 partition. Then you formatted your p3, but the bootloader still keeps the info.


Hi Ironfoot, thx for you answer.
Ok, I deleted the partition and I choosed the manual install, in order to select manually where to put 24.04.
But now I have another problem with installer, it's very unstable. But I will open another topic because this topic is resolved.