IMac – What are the requirements to use iMac screen as a second monitor – Target Display Mode

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I have a Surface Pro 4 and an iMac (late 2019). I would like to connect my Surface Pro to the iMac to use the iMac screen as a second monitor. Is that possible?

What are the requirements to use an iMac as a second screen?

Best Answer

No. You cannot do this. The 2019 iMac is not supported for Target Display Mode.

This is an attempt to write a canonical QA for this issue, as per the Meta post: Where is the list of canonical questions stored for Ask Different? I expect it to be periodically edited with the goal of becoming a comprehensive information resource.

Which iMac Models Support Target Display Mode?

  • General Rule of Thumb: If it's after 2014, Target Display Mode isn't supported.

  • 27 inch iMacs from 2009 - 2010 support TDM via Thunderbolt or mini DisplayPort (mDP)

  • All iMacs (21 inch and 27 inch) from 2011 through mid 2014 support TDM via Thunderbolt only.

  • Retina iMacs from late 2014 and on do not support TDM at all.


Which Mac models can you use as a source?

All Mac models through 2019 that meet the above requirements can use Target Display Mode. Currently, 2020 Macs will not connect (i.e. 2020 MacBook Pro running Catalina), but a 2019 MacBook Pro also running Catalina works fine.

What version of macOS is required?

  • On the Target iMac, it must be running High Sierra or earlier.
  • TDM is not supported on any iMac running Mojave or later.
  • It doesn't matter what version of macOS you're using on your source computer

Can I use my iMac as a Target Display for a PC?

Yes! As long as the target Mac meets the above requirements and the PC has the proper port; Thunderbolt or mDP. The OS on the source computer doesn't matter at all.

Can I use a "bricked" or broken iMac as a Target Display?

No. Your iMac must be a fully functional iMac running High Sierra or later.

Sources & Further Reading:

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