Thunderbolt to HDMI adapter
Bought a mini-DisplayPort adapter and used with heavy-duty HDMI cable to connect to TV; I get desktop back ground w greyed-out task bar at top rather than what is actually on the computer display. Previously used a Thunderbolt to HDMI cable and it worked fine but wore out. Trouble-shot it, cable is fine, so either the adapter is defective or the Thunderbolt port is bad. MacBook Pro 2012, High Sierra. PS adapter is Amazon Basics brand.
MacBook Pro