I realize that there can be an issue using 3TB drives with Ubuntu:
Trouble creating 3TB ext4 partition due to msdos-partition-table-imposed error
I read the answer given here but am still unsure, plus the answer is a few years old now.
The partition of free space I am trying to install to is 1.8T, so will this still cause the same problem as it's under the 2TB limit where problems start (see James Henstridge's answer above)?
I am trying to create a dual boot machine, where windows 10 is already installed, I got as far as creating the root partition as shown here:
https://itsfoss.com/install-ubuntu-1404-dual-boot-mode-windows-8-81-uefi/
However, when I try to add the swap partition I get the error above.
If this is the same problem, I'd like to be hand held through the whole process of repartitioning the dice as I really don't understand the answer above properly.