Use an iMac 21.5" (mid 2010) as a monitor, or second screen?

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Use an iMac 21.5" (mid 2010) as a monitor, or second screen?

I have an old iMac (21.5 inch, mid 2010) and I'd like to use it as a monitor, or secondary screen, connecting it to my MacBook Pro (mid 2015) which has an HDMI entrance. I bought an HDMI that connects the MacBook to an adaptor with a MiniDisplay Port that goes in the iMac, but nothing is happening. I tried restarting both computers, upgrade the OS, connecting and disconnecting, pressing Command+F2 praying, but nothing works. I've read that the 21.5 inch, mid 2010 iMac might not be compatible to work as a monitor, but some people say it is. Do I have a solution? Thanks so much

Posted on Nov 24, 2020 8:43 AM

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Answer 1

Top-ranking reply

Allan Jones

Level 9

72,926 points

Nov 24, 2020 9:11 AM in response to maiathesun

2009 and 2010 21.5-inch iMacs never supported Target Display mode, just the 27-inch versions.

Not unit the 2011 models did 21.5-inch iMacs support TDM, and that was short-lived. Apple began the deprecation of TDM when they introduced the unsupported Late 2014 iMacs, and put the last nail in the coffin early this year.

I have never heard of anyone tricking a 21.5-inch 2009-2010 iMac into working in Target Display Mode, and I've been in these forums a dreadfully long time!

You should still have the option of network screen sharing:

Share the screen of another Mac - Apple Support

Use your iMac as a display with target display mode - Apple Support

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Answer 2

rkaufmann87

Level 10

145,312 points

Nov 24, 2020 9:23 AM in response to maiathesun

+1 it will NOT work. Do yourself a favor and stop trying and purchase an external display. Much easier to connect and they are reliable.

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Use an iMac 21.5" (mid 2010) as a monitor, or second screen?

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