Clarification about using iMAC 27 inch as a separate monitor

sean yarkoni wrote:

Thank you. So if I understand correctly- I need 80$ dollars worth of above mentioned cables and to install big sur on my macbook pro?

NO!!! That is not what I am saying.

Forget Target Display Mode. Save your $80 and put it towards the purchase of a real hardware monitor.

The 13" M2 MacBook Pro (2022) cannot run any version of macOS before the one that originally shipped with it. You can't install Big Sur or Catalina on that MBP.

With respect to Thunderbolt connection hardware, the $80 of hardware that I mentioned would probably suffice for making a Thunderbolt data connection between a modern Mac and an old TB1/2-equipped Mac. For reusing an old iMac as a TDM display, the Thunderbolt hardware would be just part of the puzzle. You'd need to have all of your ducks in a row. You don't.

• Your MBP was released after 2019. You can't fix this.
• Your MBP is not running Catalina or earlier. You can't fix this.
• Your iMac is running Catalina. Downgrading to High Sierra wouldn't give your MBP the ability to use your iMac as a TDM display, but would just make your iMac theoretically able to act as a TDM display for another old Mac.

So why spend the $80 when you know that everything else that needs to work is stacked against you?

You would need $80 in specialized Thunderbolt hardware to connect the M2 MacBook Pro to the 27" 2013 iMac.

• A $50 Apple Thunderbolt 3-to-2 adapter
• A $30 Thunderbolt 1/2 cable

A much cheaper USB-C to DisplayPort adapter cable would physically fit into the ports on the respective Macs – but it wouldn't carry a Thunderbolt signal. TDM on the 2013 iMacs only worked with Thunderbolt signals.

Then you'd run into the "little" problem that Apple doesn't support letting a M2 MacBook Pro use ANY iMac as a TDM display. The M2 MacBook Pro and the earliest version of macOS that it can run are too *new* to satisfy the "2019 or earlier" and "Catalina or earlier" restrictions that Apple added on "the other Mac".

Please read Use your iMac as a display with target display mode - Apple Support.

There have been anecdotal reports of TDM working with Macs other than those described in that document, but I have not been able to personally confirm any of them. Suffice it to say if a feature is not supported, it cannot be expected to work.

Note:

Your 13" M2 MacBook Pro (2022) cannot run macOS Catalina or earlier.

• Your Mac originally shipped with macOS 12.4 Monterey. Monterey is newer than Catalina, and there is a rule that any given Mac model CANNOT run a version of macOS earlier than the one that originally came with it.
• In addition to this general rule, Catalina is an Intel-only OS. For an operating system to run on bare metal, or even inside a regular virtual machine, it must include machine code that matches the processor type. The M2 – like all other Apple Silicon processors – runs a different type of machine code that Intel processors do. Big Sur is too old for your Mac, but it at least included Apple Silicon machine code. Catalina is too old and its public releases are all written in a language that your Apple Silicon Mac does not understand.

there are other ways than target display though

Use iMac as monitor: 5 Solutions - 9to5Mac

though an imac acting as just a monitor use the same amount of power as when it was just an imac acting as computer

which is a lot more power then an external monitor you bought to use with the macbook