[ubuntu] grub-customizer not starting

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http://ubuntuforums.org – hi i tried running grub-customizer in terminal and it gives me an error: grub-customizer: /build/buildd/grub-customizer- bool GrublistCfg::compare(const GrublistCfg&) const: Assertion `piter->dataSource != __null' failed. Aborted i installed it sometime ago, and set it up to boot an iso from the menu list in grub everything works good no problems but i wonted to shorten my kernel list. i'm lost (Hardware)