Just finished virtualizing my unRAID on 6.5 update 1. I had massive problems trying to get the unRAID USB stick to show up as an available device to connect to the VM. I tried it in every USB port on the motherboard; even the ports that ESXi was using and recognising for the keyboard connection and had no luck whatsoever. Just before giving up completely I came across this VMware KB, https://kb.vmware.com/s/article/2147650. No idea why the new USB drivers don't like my Lexar USB stick, but after forcing ESXi to revert to the old USB drivers the unRAID USB stick showed up in the list of devices that could be connected to the unRAID VM. Posting just in case someone else comes across the same issue.