Grub Boot Loader Fail

Dell PC with blank hard drive.

I downloaded the latest LINUXCNC 2.9.2 and created a USB boot disk, and with the help of balenaEtcher I could sucessfully boot into Debian 12 and run the Linuc CNC software, so I figured I would install the OS from the USB drive.

It all installs until I get to Installing the Grub Boot Loader, and I get the error message "Grub-EFI-AMD64 Package Failed to Install into /Target/"
I tried a couple of times and got the same result. I have no idea what to do next.

Any help appreciated.
Rick

In BIOS, disable secure boot

Thanks for the reply.

Secure Boot was disabled when I tried the first install.

Is CMS enabled in BIOS?
Or "legacy" mode ?

I was in Legacy mode. What is CMS?

CSM = Compatibility Support Module
I have miss spelled it, sorry for that.