Be gentle with the nOOb - Pro 16 Install freeze

HI guys, TOTAL Zorin/Linux nOOb here so I need a little help installing Zorin 16 Pro on my 2010 MacPro.
Computer setup: Dual Xeon CPU, 64GB RAM, 1TB SSD (for Zorin), EVGA GEFORCE GTX 770 video card. MacOS High Sierra is boot drive (separate SSD)
Have tried installing with and without additional files downloaded and with /without NVidia drivers and letting Zorin manipulate SSD as needed. Every time get hung up on "grub-install /dev/sdb". Sometimes it just freezes while installing (I've waited as long as an hour), others it shows a dialog box stating: "Executing 'grub-install /deb/sdb' failed. This is a fatal error." When I hit OK on the latter it opens another box that says the installation is complete (of course, it is not). Rebooting takes me to start the install again.
Any ideas are welcomed. However, don't forget the n00b part!! LOL

I have about 1 minute to make a post before heading out- but don't want you to be waiting too long.
The above suggests that you need to use rEFInd to install to a MacBook:

https://www.rodsbooks.com/refind/installing.html

Aravisian: Thanks for the quick answer. Going to the rEFInd site was good case of visual overload! LOL
I should have been clearer in the fact that I am not looking for a "conventional" dual-boot (ala Zorin boot screen/picker). I use Open Core to show me a list (icon) of all the EFI partitions available (currently Mojave and the one for the Zorin (USB) installer).
My eyes got cloudy (very fast :laughing:) looking at the (Linux-laden) explanation of what rEFINd does but imagine it communicates to the (Mac) boot sequence that Zorin is available(?). I believe Open Core would accomplish the same (since it does it for Zorin installation USB stick) once Zorin is installed but I cannot get there due to the error above.
Again, thanks for the info! :+1:

UPDATE: I left the "failed" installation hang while I was typing this and I came back to a Zorin desktop! However, when I rebooted the (Open Core) EFI screen did NOT show an entry that would get me into Zorin (and I can't see it from Finder since the partition is incompatible with MacOS).

I've always been under the impression that Linux can't be installed on MAC computer's due to the proprietary nature of them. Apple don't want people to run other operating system on their hardware, so they obviously make it as hard as possible.

But these days, I've been hearing about folks like yourself, wanting to get away from Apple, and just want to enjoy the Apple made hardware, but without the BS, and having Linux on it instead. My knowledge of Apple ended after System 9.2.2

But if you get this going, you deserve a medal Rick for pure awesomeness. :grin:

LOL, I'll take the medal retroactively. I already have an old MacBook Air dual-booting with Zorin 15. However, This MacPro is older and I don't have that much expertise in messing with it. Add to that my total LACK of knowledge on Linux and......here I am! :grinning_face_with_smiling_eyes:

Yes, Zorin installed - but being unable to install to the Bootloader makes it exceptionally hard to Boot.

Only on the surface because the pages are so wordy. It's quite easy and newcomers use rEFInd all the time. :wink: Believe in yourself- you can do it.