Hexley

macrumors 65816
Original poster
Jun 10, 2009
1,457
335
I have a late 2012 iMac 27" with Thunderbolt 2 that I want to use as a display for my 2019 MBP 16" with Thunderbolt 3.

Other than the Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter would I need to get a Thunderbolt 2 cable or will a miniDisplay cable be sufficient?
 

Fishrrman

macrumors Core
Feb 20, 2009
22,205
8,249
I could be wrong, but...

... If you're going to boot and run from Catalina (standard OS on MBP 16"), target display mode won't be possible, because Catalina no longer supports it.

This doesn't matter if you have an iMac that can do it, because... again... Catalina won't support it.

I could be wrong.

Might be time to start shopping for an external display to go with the MBP 16"...
 

CoastalOR

macrumors 68030
Jan 19, 2015
2,868
1,056
Oregon, USA
This Apple article says to connect from the 2012 iMac with a thunderbolt cable to a Apple Thunderbolt 2 to 3 adapter to your MBP.

This link has some additional information.
 
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Hexley

macrumors 65816
Original poster
Jun 10, 2009
1,457
335
@CoastalOR link states it works on Catalina.

I could be wrong, but...

... If you're going to boot and run from Catalina (standard OS on MBP 16"), target display mode won't be possible, because Catalina no longer supports it.

This doesn't matter if you have an iMac that can do it, because... again... Catalina won't support it.

I could be wrong.

Might be time to start shopping for an external display to go with the MBP 16"...
 

Hexley

macrumors 65816
Original poster
Jun 10, 2009
1,457
335
This Apple article says to connect from the 2012 iMac with a thunderbolt cable to a Apple Thunderbolt 2 to 3 adapter to your MBP.

This link has some additional information.
Thank you. Now to go to hunting for used cables and adapters. I do not want to pay $100 for cables. Maybe I can get both for $40.
 

littleyellowcamper

macrumors newbie
Jul 8, 2020
1
0
I was able to get Target Display Mode to work on my 2019 MacBook Pro (Catalina 10.15.5) and my iMac 27" (also Catalina) using an Apple Brand Thunderbolt 3 to 2 adapter and a Thunderbolt 2 cable. This is my first time trying it, so I didn't realize I had to press the Comm/F2 on my iMac, NOT my MacBook. The cables cost $100 but still cheaper than a new monitor.
 

Ralphykun

macrumors newbie
Jul 9, 2020
1
0
Great news! Mine worked as well! Here is the setup and what I did to work.

MacbookPro 13" 2019 Catalina Ver 10.15.5-- Official Apple USBC to Thunderbolt 3 adapter -- official Apple Thunderbolt 2 to Thunderbolt 2 cable -- iMac 27" Mid 2011 High Sierra ver 10.13.6. First it didn't work at all, Changed port many many times and didn't work. Not sure if this help but I used MBP lower right USBC and iMac TB port right next to ethernet.
However I believe if you have a same setup, I suggest you to swap the Apple TB2 to TB2 port end. Meaning pull the cable and swap the ends. Mine all the sudden worked that way. Don't know why it should be just a straight wire but may have reset something? Anyway its working beautifully for me.

BTW, looks like you have to use an official apple keyboard to send Command F2 signal for change. I tied with BT keyboard and also virtual keyboard but never worked.
 
Last edited:

lokee

macrumors newbie
Jul 10, 2020
1
0
Great news! Mine worked as well! Here is the setup and what I did to work.

MacbookPro 13" 2019 Catalina Ver 10.15.5-- Official Apple USBC to Thunderbolt 3 adapter -- official Apple Thunderbolt 2 to Thunderbolt 2 cable -- iMac 27" Mid 2011 High Sierra ver 10.13.6. First it didn't work at all, Changed port many many times and didn't work. Not sure if this help but I used MBP lower right USBC and iMac TB port right next to ethernet.
However I believe if you have a same setup, I suggest you to swap the Apple TB2 to TB2 port end. Meaning pull the cable and swap the ends. Mine all the sudden worked that way. Don't know why it should be just a straight wire but may have reset something? Anyway its working beautifully for me.

BTW, looks like you have to use an official apple keyboard to send Command F2 signal for change. I tied with BT keyboard and also virtual keyboard but never worked.

Lucky!

I'm trying the same thing with slightly different products: iMac (27-inch, Late 2012, High Sierra Ver 10.13.6 ) -- MBP (16-inch, 2019, Catalina Ver 10.15.5) and can't get anything to work!

I have the USB-C to TB2 adapter in my MBP (https://www.apple.com/shop/product/MMEL2AM/A/thunderbolt-3-usb-c-to-thunderbolt-2-adapter) with a .5m TB2 cable (https://www.apple.com/shop/product/MD861LL/A/apple-thunderbolt-cable-20-m) running into the TB port on my iMac.

I've switched the cable around and have used all the different ports. I even downloaded Virtual KVM on my iMac to try and automagically kick up Target Display Mode. I have the official apple keyboard but the Command F2 just won't work. I can't get anything to work!

Please tell me there's some other mysterious step I need to do lol
 
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