Hi Chris,

An HDMI to HDMI connection is not possible on either of my devices.

I am trying to successfully connect on of the following options, either:

Windows 10 PC -> mDP -> DP on Dell U3415W

Windows 10 PC -> mDP -> mDP to HDMI adaptor -> HDMI on Dell U3415W

Mac iOSX El Capitan -> mDP -> DP on Dell U3415W

-Following your instructions for disconnecting and reconnecting all cables then selecting each respective input method, did not resolve the display issue.

I am still receiving, "no signal is coming from your device", whereas the each device has successfully displayed to other displays monitors without issue.

For reference, Serial # for the Monitor is: CN0PXF797426164U07UL

* Turn the Windows 10 Pro computer off
* Turn the U3415W off
* Disconnect all video cables from the Windows 10 Pro computer video card
* Disconnect every cable from the U3415W
* Reconnect the power cable to the U3415W
* Reconnect only an HDMI to HDMI cable from the computer video card HDMI out port to the U3415W far left HDMI in port
* Turn the U3415W on, then the computer
* Press the U3415W Input Source button
* Choose HDMI

Forget the adapter for now. We only want to test the provided mDP to DP cable. You need to test the computers one at a time to the U3415W using only one video in source on the U3415W.

Test #1 =
* Turn the U3415W off and Apple computer off
* Apple computer mDP out port --> mDP to DP cable --> U3415W DP in port
* Turn the U3415W on, then the computer
* Press the U3415W Input Source button
* Choose DP
* Exit the Menu

Test #2 =
* Turn the U3415W off and Windows 10 computer off
* Windows 10 computer mDP out port --> mDP to DP cable --> U3415W DP in port
* Turn the U3415W on, then the computer
* Press the U3415W Input Source button
* Choose DP
* Exit the Menu

What are the results?

With HDMI cable and Laptop see monitor but blank display, change input source to MHL it started showing.