Ubuntu server live: "Cannot delete a single partition from a device that already has partitions"

I downloaded the latest ubuntu-20.04-live-server-amd64.iso and started the installation. When I reached the storage configuration section, I chose "Custom layout". The disk already has partitions, so I tried to delete the unnecessary partitions. When selected Delete this message popped up: Cannot delete a single partition from a device that already has partitions.

The question is how do I delete them?

Solution 1:

There's a subiquity bug about this, and it looks like the installer doesn't support deleting partitions.

Your options are to erase entire disk and create partitions from scratch, or switch to a different console (Alt+F2) and use a different partitioning tool (parted, cfdisk).