I have been using target display mode with an M1 Mac mini on Big Sur for over 15 months with a late 2009 27” iMac on High Sierra 10.13.6.
It has been working fantastic using a usb-c to DisplayPort cable.
However in the past week or two, I can’t seem to get TDM to work.
Both machines are still working fine.
Have restarted both, unplugged cables, changed keyboards, etc but no luck
When plugged in and pressing Command+F2, nothing happens on the iMac, when before it would blink and switch to displaying the Mac mini…
I just tried a 13” M1 MacBook Pro also on Big Sur and also no TDM.
Is the iMac just getting too old or has there been a software update that may have disabled TDM?
IDiesel
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