2018 MacBook Pro connecting to late 2009 27" iMac Target Display Mode: Command+F2 does nothing

abp1

macrumors newbie
Original poster
May 8, 2019
4
1
I'm using an Apple USB-C to Thunderbolt 2 adapter on the 2018 MacBook Pro and a Mini DisplayPort cable (not a Thunderbolt cable) to the iMac. It doesn't work. The Mini DisplayPort cable and Target Display Mode works great with a mid-2014 MacBook Pro (with Thunderbolt 2 ports).

Would a Thunderbolt cable work?

Has anyone successfully used a 2018 MacBook Pro in Target Display Mode to a late 2019 27" iMac?

If that combination doesn't work with Target Display Mode, is there other software or hardware to display the 2018 MacBook Pro screen on a late 2009 27" iMac?

Thanks in advance.
 

chabig

macrumors 604
Sep 6, 2002
7,003
4,235
The USB-C to Thunderbolt 2 adapter does not support DisplayPort: https://www.apple.com/shop/product/MMEL2AM/A/thunderbolt-3-usb-c-to-thunderbolt-2-adapter

"This adapter does not support DisplayPort displays like the Apple LED Cinema Display or third-party DisplayPort and Mini DisplayPort displays."

Also: https://support.apple.com/en-us/HT207266

And your 2009 iMac doesn't support target display mode using Thunderbolt: https://support.apple.com/en-us/HT204592

This means that you will need a USB-C to MiniDisplayPort adapter of some sort. I see several on Amazon for around $20. I searched for "USB-C to minidisplayport".

Here is a simple adapter: https://www.amazon.com/DisplayPort-...i+displayport&qid=1557387804&s=gateway&sr=8-3

Here is direct connect cable: https://www.amazon.com/Cable-Matter...i+displayport&qid=1557387804&s=gateway&sr=8-4
 
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abp1

macrumors newbie
Original poster
May 8, 2019
4
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Thank you chabig. I appreciate your reply, especially your suggestion about trying a USB-C to Mini DisplayPort adapter, and providing a couple choices.
 

abp1

macrumors newbie
Original poster
May 8, 2019
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Thanks EugW. I think I see a solution ahead! The key seems to be a USB-C to Mini DisplayPort (not Thunderbolt) adapter or cable. I'll be testing out a friend's adapter next week. Nothing like being hopeful again.
 

EugW

macrumors G3
Jun 18, 2017
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Thanks EugW. I think I see a solution ahead! The key seems to be a USB-C to Mini DisplayPort (not Thunderbolt) adapter or cable. I'll be testing out a friend's adapter next week. Nothing like being hopeful again.
Doesn't have to be a USB-C to mini-DisplayPort adapter. Can be a USB-C to regular DisplayPort adapter.

In my case it's a USB-C to regular DisplayPort adapter, then I use a DisplayPort to mini-DisplayPort cable.

Why did I do it this way? Only cuz it turned out at the time to be a bit cheaper and easier/quicker to get the stuff.
 
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abp1

macrumors newbie
Original poster
May 8, 2019
4
1
Success! I got a USB-C to Mini DisplayPort cable and I'm reliably using my Late 2009 27" iMac in Target Display Mode with my 2018 MacBook Pro. It works great.
 
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Brayz

macrumors newbie
Nov 8, 2019
5
3
Hello!
Does the Target display mode still work with the Late 2009 iMac running Catalina? Or should it remain on a older supported version?
When pushing Command -F2 I get a black screen for 1 second and then just the iMac screen again - no success And same effect with 2014 mbpro mini-dp nor Windows with usbC to mini dp.

thanks
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Victory! For both machines! My anger management has shown that I have to push Command F2 F2 F2 F2 F2 F2 F2 F2 F2 F2 Very fast and then it switches over! Maybe it will help somebody else as well!
 
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Dcmack

macrumors newbie
Apr 25, 2020
2
0
I have a 2018 MacBook Pro 13” (Catalina) and a late 2009 27 iMac (running High Sierra.) Purchased a USB-C to mini display port cable but am unable to use target display mode. I use it with Mac mini to same iMac just fine with a Mini display pet to mini display port cable for two years so I know it can work. Seems like you guys have been able to get it going with usb-c. Any tips? Fn-2 on iMac keyboard does nothing.
 

Brayz

macrumors newbie
Nov 8, 2019
5
3
Hello Dcmack.
Yes it works with USB-C to Mini DisplayPort , but I think it strongly depends on the type of adapter. I does not work with the original apple converter on my Dell.

This one does work for me :
Secomp 12.99.3225 0.1m USB C Mini DisplayPort Zilver, Wit video kabel adapter

please do note my earlier post that just hitting Command F2 does not work for me, you have go repeatedly hit the Cmd + F2 F2 F2 F2 before it jumps over.

good luck with it!
It's wonderful when it works, I used it every day I do (home office )

kr,
niels
 

Dcmack

macrumors newbie
Apr 25, 2020
2
0
Thanks Brayz. Yes, it doesn’t work with any Apple cable or adapter that I know of, and in fact, it didn’t work at all with older Apple monitors (Mini DisplayPort models) until fairly recently. I had clients who tried, and only the Apple Cinema Display with Thunderbolt worked with USB-C/Thunderbolt 3. It was some Mojave update that made it work I believe.

After struggling with it last night after the cable arrived, I posted my question this morning. Afterwards, I gave it another try and was able to get it to work. For me, the trick was to unplug the mini display end of the cable and re-plug in while everything was running. I had tried that a few times last night without luck, but today it worked. I can now switch back and forth with Fn-2 at will. It stopped working when one Mac or the other went to sleep, and I had to reset plug again. Just finicky, but it IS working and my neck will be very happy come Monday!
 
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