Hi guys, Newbie here! Hoping I can get some advice! I've got a mac pro 5,1 2012 and I've just installed an msi radeon rx 560 4gb graphics card, ready for upgrade to Mojave. I've got a 4k monitor which I was using on hdmi without any problems on my last card, now it seems the mac only boots with the hdmi disconnected - I have to plug it in later. If the hdmi is connected on launch, the start tone just keeps repeating and mac refuses to load. I've tried on a smaller BenQ monitor (hd ready) which seems to load fine! Really don't know what's going on here! Any help/advice would be greatly appreciated! Thanks!