I've been trying to install Kubuntu 18.04 and I keep running into the same problem of the installer getting to the point where it needs to install grub and fails with the message:
Can't install grub on sda
After many hours of troubleshooting, I realized that I can get it to install if I reinstall Windows in non-EFI mode, however, this was causing some weird problems with my motherboard so it's no longer an option. I came to this conclusion via checking Disk Management on Windows. As seen in this image...
there is an efi partition. Whenever Kubuntu would install, there wouldn't be an efi partition. So I'm assuming my current Windows install is an UEFI based one. Also, when Windows is installed in UEFI mode, Disk Management initializes the other drives as GPT instead of MBR.
So my question would be what do I need to do (if it's possible) to install Kubuntu while keeping windows in UEFI mode?
Let me know if there is any more information that you need.