Trying to set up an external monitor for my MacBook Pro

I have a 2013 21.5 iMac that I'd like to use as a monitor for my 2018 MacBook Pro but cannot get them to recognize one another. Can anyone help? I'm using thunderbolt cables and adapters. Should I be using something else?

MacBook Pro 15″, macOS 11.5

Posted on Sep 5, 2021 1:25 PM

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Posted on Sep 5, 2021 6:42 PM

Encryptor5000 wrote:

You'll need to downgrade your iMac to macOS High Sierra in order to use Target Display Mode. (The MBP is fine as it is.)

That is actually incorrect. Please refer to: Use your iMac as a display with target display mode - Apple Support.

The iMac used as a display must have macOS High Sierra or earlier installed.
The other Mac that you're connecting it to must have been introduced in 2019 or earlier and have macOS Catalina or earlier installed.

Jack

4 replies
Question marked as Top-ranking reply

Sep 5, 2021 6:42 PM in response to Encryptor5000

Encryptor5000 wrote:

You'll need to downgrade your iMac to macOS High Sierra in order to use Target Display Mode. (The MBP is fine as it is.)

That is actually incorrect. Please refer to: Use your iMac as a display with target display mode - Apple Support.

The iMac used as a display must have macOS High Sierra or earlier installed.
The other Mac that you're connecting it to must have been introduced in 2019 or earlier and have macOS Catalina or earlier installed.

Jack

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Trying to set up an external monitor for my MacBook Pro

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