How to resolve 'Boot Error' message on VMWare ESXi when using a USB flash drive

Just a quick little post - I've used ESXi many times for virtusalization on servers, however older Intel motherboards always seem a bit troublesome.

The most common error I've been getting after trying to get ESXi running off a USB stick on a ~2007 Intel Motherboard was simply a black screen with 'Boot Error' in the corner. This isn't the typical error message you get - usually you'll get a generic BIOS error saying something like 'Operating System not found' - that error only shows up if there's no bootable devices detected.

If you get the 'Boot Error' message, you'r actually in luck. It means ESXi has found your drive. Simply reboot and go into your BIOS settings and hunt down an option that'll be called something like 'USB Device Emulation Type' (note that the name will vary). Change it from it's default value of 'Auto' to either 'Fixed Device/Disk' or 'Hard Drive'.

The issue is that your motherboard 'advertises' the USB drive as a small external storage device. This gets treated differently when booting to how a physical hard drive was. By changing the option, the USB drive is handled as a fixed device, resolving the issue.