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Mac no longer detects external display via Thunderbolt/HDMI adapters

I used to have an external monitor via Thunderbolt HDMI adapter, but I reinstalled the OS and now it won't recognize an external monitor at all. Tried troubleshooting and Apple article on external monitors, nothing. Help!


iMac 2011, 10.13.6 High Sierra

iMac 21.5″, macOS 10.13

Posted on Feb 2, 2021 10:08 AM

Reply
Question marked as Top-ranking reply

Posted on Feb 2, 2021 10:31 AM

Hi RogMarq,


What external display are you trying to use? 


Have you tried reading this article, Get help with video issues on external displays connected to your Mac - Apple Support?


Also, try resetting:


Cheers,


Jack

1 reply
Question marked as Top-ranking reply

Feb 2, 2021 10:31 AM in response to RogMarq

Hi RogMarq,


What external display are you trying to use? 


Have you tried reading this article, Get help with video issues on external displays connected to your Mac - Apple Support?


Also, try resetting:


Cheers,


Jack

Mac no longer detects external display via Thunderbolt/HDMI adapters

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