Unfortunately Elgato doesn't provide Mac drivers for the HD, HD60, or HD60S that work with OBS, so you can't add them as a video capture device. You'll have to run their software in fullscreen and capture the window instead, or replace your card with the Camlink. Elgato will not be providing drivers. A video tutorial is available at http://www.youtube.com/watch?v=vO0zrNzDhVE
Yes, it's unfortunate that so many Mac users buy ELgato products thinking they will work. The box says Mac compatible. I went through the same frustration after buying the Elgato HD. Elgato blames the MAC OS saying its extremely difficult to create a driver for OBS... But somehow their devices are magically seen on a Mac when you use THEIR streaming software.
yeah - it's elgato writing software thats at fault here, not the mac... As others have said there are plenty of tools that do work like the blackmagic encoder .. which is also natively supported in OBS btw.
I'm looking for a good value Mac-compatible capture device myself, so checked these out. They're great devices (yay for Thunderbolt!) but their tech spec page seems to support 1080 capture at 60 interlaced, not 60p. That's a problem for me, but might not matter for others.