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Can't use iMac as monitor for new MacBook?

I have no problem using my iMac mid 2011 as monitor for my old Macbook Pro (2017, macOS Catalina 10.15.7) using a Thunderbolt 3 - thunderbolt 2 adapter.


However, it doesn't work if i plug my new Macbook Pro (2020, macOS Big Sur 11.0.1) into the same set up.


The ports on the Macbooks are identical and using the same exact set up.


Could it be bc of the 2020 mac is running a later software?

MacBook Pro

Posted on Jan 21, 2021 10:02 AM

Reply
Question marked as Top-ranking reply

Posted on Jan 21, 2021 10:12 AM

No, it is because Apple dropped TDM from all 2020 Macs early last year. The TDM support article is now archived so not fully up to date, plus it's poorly written, so here is a condensed version that incudes newer products:


VIDEO SOURCE COMPUTER (the one sending the video signal to an external monitor):

    • A 2019 or older Intel Mac running macOS 10.15 Catalina or older.
    • Apple Silicon Macs are not supported
    • mac OS11 Big Sur is not supported.


TARGET COMPUTER (the one to be an external monitor):

    • An iMac 27-inch (Late 2009 and Mid 2010)
    • any iMac from Mid 2011 to Mid 2014.
    • The target computer must run no higher macOS than OS 10.13.X High Sierra


Apple started the deprecation of TDM in 2014 (!) and threw the last shovel of dirt in its grave is early 2020.


3 replies
Question marked as Top-ranking reply

Jan 21, 2021 10:12 AM in response to Sebsation

No, it is because Apple dropped TDM from all 2020 Macs early last year. The TDM support article is now archived so not fully up to date, plus it's poorly written, so here is a condensed version that incudes newer products:


VIDEO SOURCE COMPUTER (the one sending the video signal to an external monitor):

    • A 2019 or older Intel Mac running macOS 10.15 Catalina or older.
    • Apple Silicon Macs are not supported
    • mac OS11 Big Sur is not supported.


TARGET COMPUTER (the one to be an external monitor):

    • An iMac 27-inch (Late 2009 and Mid 2010)
    • any iMac from Mid 2011 to Mid 2014.
    • The target computer must run no higher macOS than OS 10.13.X High Sierra


Apple started the deprecation of TDM in 2014 (!) and threw the last shovel of dirt in its grave is early 2020.


Can't use iMac as monitor for new MacBook?

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