I don't know if this was caused by the software or faulty flash drive. It appears that the error occurred when Rufus was trying to convert MBR partition on the flash drive to GPT. It is detected by windows explorer as well as diskpart etc but has no partition. Please have a look at that and do not ask me to try the suggestions given there as I have tried all of those and nothing has worked. USB totally damaged after used with Rufus So this is almost identical situation to the post below.
