I'm a huge fan of Ubuntu, and I have been using it as my main OS for about 2 years now. I never had any issues with it until now when I have to dual boot (work requirement) with Windows.

I followed a guide how to install Ubuntu, and Windows and took the decision so simply start from scratch as it seems easier (since all guides said I should start with installing Windows).

So, I got myself another SSD (I want to have Windows on one and Ubuntu on the other one. I then started to install on sdb, so far so good, Windows starts fine. It created an EFI drive, and a system, etc. Whatever Windows needs.

However, now I wanted to install Ubunutu 18.10 on my PC on my other SSD. I created a USB installer and followed the normal steps until I came to pick drives, there I picked "Something Else" (I think that is what is it called) and re-portioned my other SSD (sdc) so half of it was the OS, and the other half my home folder. For the boot drive I have tried picking (sda, sdb and sdc), however, whenever I pick another drive than the Windows EFI drive as first boot option, I get straight into grub-rescue and can't do anything. :( If I move back over to making the Windows EFI drive, I get straight into windows and all works fine. I tried re-installing Ubunutu over and over again with different options but nothing worked.

Could someone explain the installation process to me like I'm 3 years old and can't even start the PC without my parents clicking the on-button? Because I just can't get it too work, and I miss having Linux as my main OS, I only want to boot in to Windows when I work from home, not always.

I'm not sure I understand all the options with /, /home, /boot, and the swap, EFI etc. when I create new drives.

sda = A regular HDD, 2 tb that I have partioned so 500 gig is for windows, and the rest I would like to partion as a second "home" drive for Ubuntu, that mounts automatically when I start Ubuntu, however, I have never figured out which option I need to pick for this one? sdb = Windows drive and all the folders it automatically creates when installing the OS. sdc = My other SSD where I want to have my /(OS), /home and SWAP.

However, like I said, I just can't get it working and I would really love any help at all to learn more about this and what it all means. I have tried reading several tutorials, but I just don't get it. :(

Update 1 It seems Ubuntu does NOT install in UEFI mode but in Legacy, and windows is installed in UEFI mode, how do I change this for Ubuntu when installing? The USB is also a UEFI (I turned of Legacy mode completely in my motherboard settings), but for some Ubuntu and Grub just won't work... – Zero just now edit

Thanks in advance!