Using a 2013 Mac as a monitor

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Using a 2013 Mac as a monitor

I have a late 2013 Mac running macOS Catalina v10.15.7. I wanted to ascertain if there’s anyway I connect my work laptop a 2024 IBM Lenovo Thinkpad to the Mac so to use it as a monitor?

To note as it’s a work laptop I cannot add software, apps or hardware but it would need to be possible by using an appropriate cable connection between the 2.

Thank you

iMac 21.5″, macOS 10.15

Posted on Oct 15, 2025 5:05 AM

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Answer 1

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Servant of Cats

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31,925 points

Oct 15, 2025 8:15 AM in response to PC44

That iMac supports Target Display Mode using Thunderbolt input.

However, there are multiple reasons why that won't do you any good.

Your iMac is running Catalina. You'd need to downgrade to High Sierra (or earlier) to use Target Display Mode.
Target Display Mode on that Mac requires Thunderbolt input
Making a connection from a modern version of Thunderbolt (that lives on USB-C) to the older version that the Late 2013 iMac has would require $80+ of specialized Thunderbolt connection hardware.
Even if your IBM/Lenovo notebook had a Thunderbolt port, Apple added restrictions on Target Display Mode – such that the only supported video sources are other old Macs. So you'd be spending the $80+ for nothing.
Your tag line indicates that you have a 21.5" iMac with a resolution of 1920x1080 pixels. These days, you can purchase some standalone 24" 1920x1080 pixel monitors for $80, and even the ones which have IPS screens, and basic color accuracy (100% or near-100% coverage of sRGB) might go for $150 or less.

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