I want to use my iMac as a monitor for my MacBook Air. I have a thunderbolt cable I got from Apple today. My iMac has macOS Sierra version 10.12.6 and my MacBook Air has macOS Big Sur 11.4. When I press command F2 the iMac just has a grey screen. I have tried the trouble shooting tips by Apple to no avail.
Unfortunately, that setup is not supported by Apple. The iMac cannot be used as a monitor for any of the newest Macs and target display mode is no longer a feature of macOS. It is wholly unsupported in macOS Big Sur.
As Apple states them, here are the rules for target display mode on iMac:
click> https://support.apple.com/en-us/HT204592
Per the link above:
• Make sure that your target iMac is using macOS High Sierra 10.13.6 or earlier.
• The source Mac must have been introduced in 2019 or earlier and have macOS Catalina or earlier installed.
Unfortunately, that setup is not supported by Apple. The iMac cannot be used as a monitor for any of the newest Macs and target display mode is no longer a feature of macOS. It is wholly unsupported in macOS Big Sur.
As Apple states them, here are the rules for target display mode on iMac:
click> https://support.apple.com/en-us/HT204592
Per the link above:
• Make sure that your target iMac is using macOS High Sierra 10.13.6 or earlier.
• The source Mac must have been introduced in 2019 or earlier and have macOS Catalina or earlier installed.
Thanks. That is too bad. I guess I will return the thunder cable.
How to get the iMac to work as a monitor
