ubiquity is not installed after the install from the ISO installer. That's why I didn't know I could use ubuntu-bug to report about this problem.
To the user it doesn't matter if the window that is shown during the install is a warning or an error. It's just unnecessary to show it on a non-UEFI installation.
I wrote the Ubuntu MATE 22.04.2 ISO to a USB stick with Rufus using Rufus' dd write mode. This is enabled by pressing alt-i after starting Rufus. The installation from the USB stick worked well.
ubiquity is not installed after the install from the ISO installer. That's why I didn't know I could use ubuntu-bug to report about this problem.
To the user it doesn't matter if the window that is shown during the install is a warning or an error. It's just unnecessary to show it on a non-UEFI installation.
I wrote the Ubuntu MATE 22.04.2 ISO to a USB stick with Rufus using Rufus' dd write mode. This is enabled by pressing alt-i after starting Rufus. The installation from the USB stick worked well.