Also, if I connect the input (MacBook) directly to the system bypassing the splitter it works absolutely fine.

When I switch the input to an Xbox 360 everything works absolutely fine. Keep in mind that the input I'm using is from a MacBook Pro. However, if I connect a projector to the other output channel it stays working fine on that. HDCP is a content protection system that can be applied to DVI, HDMI, and DisplayPort. NVCleanstall also makes sure MSI only gets activated on NVIDIA GPU devices. However, four seconds after I connect my capture card to one of the splitter's output channels the splitter just stops outputting on that channel and essentially shuts that channel off (as seen by the LED on it). HDCP is a feature of the new MacBook and MacBook Pro, and this is a feature that I actually welcome. Probably the Switcher/Splitter thinks this is advice that can copy and so is flagging it's copy protection protocols, or some such (Not an expert on this aspect of everything!) I think I can probably bypass this problem by buying a separate HDMI Splitter to feed directly from the laptop to the ATEM, and split to the Switcher for the TV, but I would rather not buy anymore hardware for this as this StarTech device should do what I need, and does for every other aspect.Hey so what I'm trying to do is take HDMI input (from a computer) to a splitter from which one channel goes to some viewing device (projector or something) while the other channel goes through a capture card into another system for some processing that I'm doing.

From everything I have read and tested and all the tech support people I have spoken with, both at Blackmagic and StarTech, it seems that the issue lies with the EDID of the Blackmagic devices, and/or the HDCP. I am using the StarTech 2x2 Matrix (VS222HD4K) and I have tested all cables and input/outputs, everything works correctly, I can even send a signal from a camera (HDMI out) to the Switcher/Splitter (HDMI IN and OUT) to both a TV (HDMI in) and the ATEM (either HDMI in or SDI in via Blackmagic HDMI to SDI converter), but it won't allow me to send a signal from my laptop (HDMI Out) even when I have no programs open and am just showing the desktop (Either mirrored or extended) yet at the same time it will allow it to feed to the TV! I have tried plugging directly in the the ATEM, through the HDMI - SDI converter, from the converter to an SDI monitor, and directly into the Ultra Studio Mini Recorder (Both via HDMI and converted to SDI), none of them allow the laptop to pass a signal. The problem comes when I try and use an HDMI switcher and splitter in one.

So I'm setting up a moblieish broadcast system and the boss just decided he wanted one more feature, split a laptop (Macbook Pro 2014) with graphics to the ATEM switcher and a Television in the background of the shot.

Macbook pro hdcp issues