oldfred: I haven't installed Windows or any OSes on the drive. It had an NTFS partition on it -- I guess within a gpt table -- when I got it, and I've deleted that partition and replaced it using gparted. Would that cause the MBR/GPT confusion?
idoit: Both partitions are empty and put there by me. It's a good-sized drive, and I want to use the rest of the space for general file storage. The small partition is for the gparted live installation, which has to have FAT32, apparently. But I don't want the other files on a FAT32 partition and I don't want the gparted live installed on the same partition as the files I want to store, that's all.
I have to admit that I don't understand the problem of your external HDD, so I am reading and learning...
If it was gpt and you used gparted to repartition, not Windows then I would normally think it is ok. But you got the warning message on gpt data.
Did you try fixparts? It may tell more.
I think my previous post was directly booting ISO from a USB flash drive. But you can do the same from a hard drive. I never had an install go so fast as one from a spinning hard drive ISO to my new SSD. I had thought the USB flash installs were quick compared to CDs. :)
This will boot an ISO from a hard drive.
ISO Booting with Grub 2 from Hard drive - drs305
Boot ISO from harddrive. To install it would have to be different partition
[SOLVED] Using grub 2 to boot an iso off hard drive