XPS 13 (9343) and Linux USB stick

Greetings.  Anybody here using Linux on a usb thumb drive?  I can't seem to get TAILS to boot from a SanDisk USB thumb drive.  On the XPS 13, the boot order is set to TAILS first followed by Window boot manager then Windows, but no luck. 

Tails 1.4 created with Universal USB Installer 1.9.6

Thanks for your help.