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I have two external monitors (both are Sanyo TVs). My Macbook Pro has one Thunderbolt. I purchased a Mini DisplayPort to Dual HDMI Adapter. The adapter is connected to the Mini Display port and to a USB. I have two HDMI cables, each connected to their own HDMI port in the adapter. My problem: The laptop works just fine independently; however, the two external monitors mirror each other. I have tried clicking on Display and clicking on Detect Displays but it does not detect the 3rd monitor or if it does, I am unable to make it work independent of the 2nd monitor - Help, Please!