I have three hard drives, one SSD two normal HDD's, the problem is that i want to dual boot windows 10 (installed on the SDD) and Ubuntu 14.04/16.04 on a 600 GB HDD, installing goes pretty well but it doesn't detect my windows 10 drive. I have a UEFI boot
First, is your Ubuntu in EFI mode ? You can check with this
[ -d /sys/firmware/efi ] && echo EFI || echo BIOS
I do not think it can detect EFI boots if it is in BIOS mode.