current latest download of LinuxCNC V2.9.8 will not install GRUB on several PC's

> that looks like its looking on the cd/DVD. If this is not on installation, edit your sources file to remove the CD/DVD settings

I'm not sure whether the cdrom:// is referencing an actual CD or it's looking on the USB key that I had flashed with the image. I wasn't hearing any attempted access to the DVD drive though that might not mean much. (Do you know?)

The installation worked after I rebooted and ran through the installation from scratch and let the thing have an Internet connection (DHCP lease FWIW) to do what it wanted to do. Going back and reconfiguring the network and package portions without rebooting was not enough to resolve the GRUB installation issue.

I’m not sure who you are replying too, but on my original post about failing the install at grub install, yes I could load the live version without any errors
It was only on any of the install option that it’s failed at grub unless it had access to the internet either wired or Wi-Fi

Boots and works perfectly in live mode. The same system loads and runs Windows XP with zero faults, and will boot and run an old Mandrake linux installer USB with no errors. (OLD! Like kernel 2.2!) Of course, the NIC doesn't work with Mandrake, but everything installs. It won't boot after because of the lack of UEFI support, but it does install.

Depronman, the reason I jumped in on this thread with you is that I think I might also be having a network installation error. I am wondering if it's relying on having internet access to download any missing packages that it needs, and that it's missing a few critical packages if it can't get internet access.

I installed LinuxCNC 2.9.8 on a virtual machine a few weeks back. It also failed during the grub installation phase. I'm 99% that at least in my case, something with the automatic network configuration did not work properly, and this caused the grub installation to fail. If I recall correctly, the DNS server was incorrectly set, and I had to manually edit /etc/resolv.conf to put the correct DNS server first.

No problem at all I was just a little unsure who Tommy was replying too
I think the grub problem that you are seeing is down to lack of internet
Both myself and friend of mine who knows linux FAR better than I do experienced the same issue with the 2.9.8 iso when trying to install with no internet present

So whilst trying to install you effectively had no internet connection
Same result that myself and friend of mine experienced

My guess is Rufus is the problem, create a new ISO with Balena Etcher

How would Rufus be the problem? If the liveCD version runs, then the ISO has been written properly, and it's easy enough to run the verification check before using it as bootable media.