I have ubuntu 12.04.05 LTS. I've downloaded ubuntu-16.04-desktop-amd64.iso. When I run "Startup Disk Creator" and select ubuntu-16.04-desktop-amd64.iso to write to my usb stick. Then I restart, change my bios to boot from the SANDISK USB. I end up in a live CD of ubuntu 12.04. Which is what I already have. I know I'm running on the usb stick as my desktop is clean and my background image is missing. System Settings Details shows ubuntu 12.04 LTS.
I have used gparted to create partitions on another usb stick, then used dd to copy the iso file to the usb device. Then rebooted, again selecting the SANDISK USB in the bios. And do end up in an ubuntu 16.04 LTS live usb drive. But if I'm having this problem then perhaps others are too?
For some reason it appears that Startup Disk Creator for ubuntu 12.04 doesn't write the selected iso file? Also SDC does not show a version number.