Can I use my existing late 2012 21" iMac (macOS Catalina installed) as a secondary screen for my brand-new 2019 iMac 21" with macOS Catalina?
Meaning iMac as extended screen for another iMac?
(I have seen no posts until now on this subject)
iMac Line (2012 and Later)
Use your iMac as a display with target display mode - Apple Support
You need a Thunderbolt 3 adapter
Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter - Apple
and a Thunderbolt cable.
https://www.apple.com/shop/product/MD861LL/A/apple-thunderbolt-cable-20-m
It will not work with Mini DisplayPort, even though the connectors will fit. Do not use any non-Thunderbolt cables or adapters, such as HDMI.
If the 2012 iMac is running Mojave or Catalina, you will have to erase it and install High Sierra.
Use your iMac as a display with target display mode - Apple Support
You need a Thunderbolt 3 adapter
Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter - Apple
and a Thunderbolt cable.
https://www.apple.com/shop/product/MD861LL/A/apple-thunderbolt-cable-20-m
It will not work with Mini DisplayPort, even though the connectors will fit. Do not use any non-Thunderbolt cables or adapters, such as HDMI.
If the 2012 iMac is running Mojave or Catalina, you will have to erase it and install High Sierra.
Hello
I've ordered Thunderbolt 3 USB-C to Thunderbolt 2 converter + Thunderbolt 2 extension cable and hooked 2 iMac screens together.
It works under Os Catalina!
PS You can however not spread a large (wide) window over 2 screens yet...
This is not working for this particular iMac-iMac constellation, hence my question.
I have on the one side Thunderbolt 3 bus (USB-C connector) Firmware version 1.34.0 40 Gb/s on my 2019 iMac and Thunderbolt 2 bus (Mini Display Port Connector (type 2?))Firmware 0.12.3 10 Gb/s on my 2012 iMac.
A local @reseller sold me the following kit ;-)
1x USB-C to HDMI (Sitecom) +1x HDMI-HDMI (Belkin high speed) + 1x HDMI-Mini Display Port (hama)
After connection nothing happened.
What went wrong?
maybe too many converters
if it was me then I would convert usb-c(thunderbolt3) to minidisplayport connector (thunderbolt2)
both thunderbolt3 and thunderbolt2 use displayport signals to convert displayport to hdmi and then back to displayport seems like an unnessesary source of issues.
more about displayport and thunderbolt
I will order the suggested converter and let's take it from there.
Keep u posted.
regards
Why do i have to erase Catalina?
I just installed the Os...
Use your iMac as a display with target display mode - Apple Support
"Target display mode requires macOS High Sierra or earlier on the iMac used as the external display. It does not work with macOS Mojave or later."
There have been reports of it working with Catalina, but there could be occasional problems.
Re spreading window across two screens, make sure "Displays have separate Spaces" is not enabled in "Mission Control" system preference.
How do i use my 'old' 2012 iMac as a secondary screen with my 2019 new iMac?
