Target Display Mode for: iMac 21.5-inch, 2017 (with BigSur) connected to MacBook Pro 16-inch, 2020 (with BigSur)

Hi leandro76,

Thanks for using Apple Support Communities. We understand you have some questions about compatibility of target display mode. We're happy to provide some information to help.

macOS Big Sur 11 doesn't support Target Display Mode. To use Target Display Mode, you would need a compatible Mac using macOS Catalina 10.15 or earlier.

You can see more about using an external monitor with your Mac here: Use external monitors with your Mac

Thanks.

leandro76 wrote:

As the title reads, does Target Display Mode work for iMac 21.5-inch, 2017 (with BigSur) connected to MacBook Pro 16-inch, 2020 (with BigSur)?

I have the Thunderbolt 3 cable but is not working when I press Command + F2.

Any help?

Thanks!

What are you trying to accomplish—

There are caveats here—

Use your iMac as a display with target display mode

note: With target display mode, you can use your iMac as an external display for another Mac.

This article has been archived and is no longer updated by Apple.

https://support.apple.com/en-us/HT204592

leandro76 wrote:

Seems quite clear by now you need an alternative for an external display 😉

Using 4K displays, 5K displays, and Ultra HD TVs with your Mac - Apple Support
 https://support.apple.com/en-us/HT206587

Use the LG UltraFine 5K Display with your Mac or iPad Pro https://support.apple.com/en-us/HT210205

32-inch Retina 6K display https://www.apple.com/pro-display-xdr/

My "cliff Notes" version that tries to clear up the confusing presentation of supported models and OS versions in the now-archived Apple support article:

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.

neuroanatomist wrote:

Apple dropped support for TDM a while back, and regardless it did not work with iMacs after 2015.

Yes that is the caveat that is spelled out in the apple link above...

All iMac models introduced in 2011, 2012, 2013, and mid 2014. Full stop.

Apple dropped support for TDM a while back, and regardless it did not work with iMacs after 2015.

You might consider Luna Display.

https://shop.astropad.com/

... and no support in Macs after 2019 models.