Redundant boot entries

Trying to remove old boot entries from grub. Used grub customiser but they always re-appear. How so I update grub?

Can you be more specific about “old boot entries” and “grub customiser”, please?

Normal way to update grub2 is:

grub2-mkconfig -o /boot/grub2/grub.cfg

That searches for other operating systems and adds those to the menu. If you don’t want that searching, you can turn it off (in Yast bootloader, uncheck the “Probe Foreign OS” box in the “Bootloader options” tab).

How many Kernel have you installed?

https://en.opensuse.org/SDB:Keep_multiple_kernel_versions