windows 10 boot camp external ssd thunderbolt

Hello everybody I want to test parallels, but il's doesn't work... My configuration : Imac Retina late 2014 (3,5 GHz Intel Core i5) 27 inchs with 24 go of Ram.. I have Windows 10 Boot Camp External SSD Thunderbolt like here : Everythings works very well and fast .... BUT When i launch...