How can I use my 2011 iMac as a monitor for my 2023 MacBook Pro?

Hi,

A MacBook cannot directly display to an iMac using Target Display Mode (TDM) if either machine is too new. TDM, which allowed older iMacs to act as external displays for other Macs, has been deprecated by Apple for newer models. Additionally, even if TDM were supported, the specific iMac and MacBook models might not be compatible due to software and hardware limitations. 

Here's a more detailed explanation:

• Target Display Mode is Deprecated:
• Apple has removed the Target Display Mode functionality from newer iMac models and the software restrictions for TDM mean that older iMacs can't be used as external displays for newer MacBooks. 
• Software Compatibility Issues:
• Even if the hardware supported TDM, newer macOS versions on the MacBook might not be compatible with the older macOS versions required on the iMac for TDM. 
• Alternative Display Options:
• If you need to use an iMac as a display for a MacBook, you'll need to explore alternative methods. One option is to use AirPlay, but this is primarily for mirroring and may have lag. Third-party apps like Duet Display or Spacedesk are also available for screen sharing, but these may also have limitations. 

cawelch wrote:

I've seen some negative answered to this question and I can't get the Target Mode method to work. But I continue to wonder why it won't work

2011 iMacs support Target Display Mode using Thunderbolt input. But Apple added restrictions on Target Display Mode such that no current Mac supports using any iMac as a Target Display.

See the bad news here: Use your iMac as a display with target display mode - Apple Support

Hopefully you have not spent $80+ for specialized Thunderbolt hardware to try to make the connection. That hardware would now only be good for making a data connection, not a video one.

especially since my MacBook can receive the AirPlay display of the iMac.

Your 2023 MacBook Pro is new enough to support being an AirPlay Receiver for AirPlay to Mac. Your 2011 iMac is not. Because Macs were able to AirPlay to Apple TV set-top boxes long, long before they acquired the ability to be AirPlay Receivers, your 2011 iMac probably sees your 2023 MacBook Pro as being a sort of AppleTV box.

See the AirPlay to Mac section of: Continuity features and requirements for Apple devices - Apple Support

Why can't the MacBook display to the iMac?

Your new Mac is too new to use the iMac as a Target Display, and your old Mac is too old to be an AirPlay Receiver.

Target Display Mode has been dead over 10 years, since 2014 so no, you cannot use your iMac as a display for a 2023 MBP. Please carefully read Target Display Mode and you will find your MBP is too new and the iMac likely does not have the correct version of Mac OS installed. In short, if you need an external display for your MBP please simply buy one, they begin at less than $100 are easily found in a variety of display sizes and feature sets. This is also a major advantage for a number or reasons:

• Simple setup
• No expensive cabling required
• Dead Reliable
• Cost effective

By the way your question is asked almost daily on these forums and if you research you will find my answer is correct.