Why doesn't my 20 inch 2009 iMac support target display with my 16 inch 2019 iMac?
I have an HDMI plugged into a thunderbolt USB-C adapter in my MacBook but when I hit Command F2 on my iMac it fails to activate target display. Simply wondering why that doesn't work? Any information helps, thanks!
MacBook Pro 16″, macOS 10.15
Your Early 2009 20” does not support Target Display Mode.
Only a Late 2009 - 2010 27” or the 2011 - Mid 2014 iMac’s support Target Display Mode.
For all the details, see > Use your iMac as a display with target display mode - Apple Support
Your Early 2009 20” does not support Target Display Mode.
Only a Late 2009 - 2010 27” or the 2011 - Mid 2014 iMac’s support Target Display Mode.
For all the details, see > Use your iMac as a display with target display mode - Apple Support
Easy because they don’t! Only late 2009 27” to 2014 iMacs did and even then not all models. To be honest you are much better off buying an external display.
Target Display Mode
