Lets start one more thread about Dell screens an issues with MST. I got a Surface Pro 3 daisy-chain connected to two U2415 screens. As soon as the SP3 goes the sleep the screens never wakes-up. If power cycling the monitors, the SP3 will find them again. Same issue with a Lenovo and HP laptops. Can just confirm what the rest of internet already have figured out. Ship them back to Dell and get a refund, because they will not try to fix the issues.