Error when attempting to import an Ubuntu image - ClientError: Unable to determine kernel version.

Since you've already hidden the duplicate grub.cfg and confirmed the kernel is supported, the next step might be checking the image metadata and ensuring that the necessary kernel files are in the correct locations for the importer to recognize them. Sometimes, the importer struggles with the way boot settings are configured, especially with customizations in Ubuntu images. Double-check that your /boot/grub/menu.lst or grub.cfg files are pointing correctly to the kernel version. You could also try mounting the image and confirming that the kernel is accessible from within the system itself. Additionally, reviewing the logs from the import task might provide more specific clues about where it's failing to detect the kernel.