Bootable usb not detected in boot menu Acer Nitro 5

@SazzAspire3, do create a new thread, let's try to keep the community organized and easy for everybody so search through.

But from what you say it's Ubuntu that's to blame and not Acer, their installer won't let you install even to an external drive if it can't access the internal disk, because the animal decides to modify the internal drive instead under UEFI and keep the boot code in the ESP partition of the internal drive instead of creating a new one in the external drive, which is useful if you plan on booting with that drive across several computers.

Do create a new thread and tag me if you want so I get notified, I'll try to guide you on the proceeding, but I can already tell that I have no idea how to install Ubuntu with its installer so that it works like that. Arch for example I have no problem with, probably the same with other distributions, but Ubuntu... last time I checked I had to delve into ubiquity's code (its installer) and it was a pain in my derrière.

Had the same issue. The option to boot from USB was not appearing in the Boot Menu. Turns out the reason was that I didn't format my USB drive in FAT32 format. But the issue was that the FAT32 option was not appearing for me. The reason is because my USB was 64 GB and FAT32 option is only available for disks smaller than 32 GB. So I bought a new USB of size 16 GB and then created a bootable disk using Rufus and GPT. I didn't had to change any of the BIOS settings either. It worked then as the option to boot from USB started appearing.

By the way the FAT32 limit of 32GB is mentioned and explained here.

https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/winpe--use-a-single-usb-key-for-winpe-and-a-wim-file---wim?view=windows-11

https://www.theregister.com/2021/01/04/windows_format_fat32/