I've got a recently purchased Mac mini connected to an old iMac via a USB-C-to-miniDisplayPort cable. Everything works fine except for when I first power the Mac mini on -- the iMac briefly shows the Apple logo, and then the screen goes dark. To actually see the video, I have to disconnect and re-connect the cable. After this, everything is fine, including if I let the Mac mini sleep the display. 
I installed VirtualKVM on the iMac, which made no difference. I'm wondering if the issue is the cable?
	
		
			
		
		
	
				
			I installed VirtualKVM on the iMac, which made no difference. I'm wondering if the issue is the cable?