I have a Dell Latitude e6440 with 8GB Mem and 256 SSD Hard disk upgrade running windows 10. The disk has 3 partitions (C: boot, recovery, EFI system) C: partition shows 192GB free space. I want to install Ubuntu. Problem is when I try and shrink the C partition it only allows me 12GB where I need 15 to 20GB. Where is the other 150GB?