For my own use, I researched and successfully tested methods of integrating an M1 Mac mini with a Thunderbolt Display and up to to two iMacs in Target Display Mode. My focus was on minimizing expense since both my Late 2009 iMac and Thunderbolt Display are aging. So I've identified low cost interface items that are currently available on Amazon. For a single iMac, the interface items are less than $40. For the Thunderbolt Display, the cost is < $50. The attached PDF should make clear how to get this done. You can go all out with three displays or just one. Note that you can use only one of the M1 Mini's Thunderbolt ports for a display unless you turn to something like a DisplayLink adapter. The options I've included are focused on employing existing Apple screens that you may already own and they should not add additional calculation burden on the CPU in the way DisplayLink appears to. Some of this should be applicable to M1 laptops and I hope this helps someone!
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How to Integrate M1 Mac mini with Target Display Mode Thunderbolt Displays (Up to 3 Displays!)
- Thread starter curtc757
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I forgot to mention that I tested with Big Sur 11.0.1 and that if you have enabled screen sharing on the iMac, you will be able to run its applications using the Apple Screen Sharing app on the Mac mini. This is almost like having a fourth screen with the swipe of the trackpad. That's a pretty cools capability if you're using the old iMac as a file server or for legacy apps.
I don't THINK that is currently possible. It seems like Apple have designed the M1 Mini GPU to support two external displays with one permanently allocated to the HDMI port and the other to either of the Thunderbolt ports. People are getting additional displays to work with external graphics hardware (i.e. DisplayLink HDMI or DisplayLink DisplayPort) driven by the USB-C ports, but I don't think those will drive your second TB Display. You could originally daisy chain a second TB display using the port on the back of the first. But I think that if you do that with the M1 you will probably get one working and the second with a black screen. You should definitely try it though if you have the cables and report back!
I've tried 1a with a iMac (27-inch, Mid 2011) and I can't seem to get it to go. Do you have to hit any buttons, such as Command F2 to enter Target display mode?
I don't think you're going to get 1A to work for you because your port on a 2011 iMac is a Thunderbolt port. So it's not going to work with a DisplayPort cable. I believe you will have to do something more LIKE 1B but you will have to add a thunderbolt 2 cable where the blue line is shown. So you will end up with a Thunderbolt 3/2 adapter and a Thunderbolt 2 cable. I strongly recommend you buy those both from Apple to avoid a lot of hassle - unless you can find a specific cable someone has tested. Then once connected, yes you will have to have a keyboard attached to the iMac and invoke Cmd F2. You may need to invoke it repeatedly to get it going. Here are two articles on TDM. One how to, and another from Apple. Note that Apple says that you must have MacOS High Sierra or earlier on the iMac used as a display, however my Late 2009 iMac has a patched version of Mojave, so your results may vary. I suspect the guys doing the patch bypassed whatever was disabled. Good Luck to you!
www.lifewire.com
support.apple.com
These are key points from Apple's doc:
How to Use Your Old iMac as a Monitor
Target Display Mode can turn iMacs made between late 2009 and 2013 into a monitor for use with other Macs. Here's how to do it, and what limitations exist.
Use your iMac as a display with target display mode - Apple Support
Target display mode is a feature available with certain older Mac models.
These are key points from Apple's doc:
- All iMac models introduced in 2011, 2012, 2013, and mid 2014: Use a Thunderbolt cable to connect your iMac to a Thunderbolt or Thunderbolt 2 port on the other Mac. If the other Mac uses Thunderbolt 3, you can use the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter with your cable.
My original post is for iMacs that have DisplayPort video ports. I apologize that I wasn't clearer about that. If your iMac is 2011 to mid 2014, it has a Thunderbolt port and you will not get Target Display Mode working with a DisplayPort cable. You will need to use a Thunderbolt solution.
Ah, got it. Thank you for your help. I do have a thunderbolt 2 to thunderbolt 3 setup. It works with Target display mode between my 2019 macbook pro and the mid 2011 27" imac, but I can't seem to get it to go between the m1 mac mini and the mid 2011 27" imac. Any ideas there?
Hmm... I don't know what would cause that unless you already have a display on one of the thunderbolt ports. You will NOT get two thunderbolt displays to work via the two USB-C ports. People are getting DisplayLink adapters to work on those though. A single Thunderbolt solution should work - except possibly for that Apple caveat about having an older OS on the iMac. The only thing I can think to recommend is detaching the cables from both machines, reattaching, and then doing the Cmd F2 thing repeatedly to see if it will fall in line. If that fails, there is still option 3 though that's a little more pricey. It does provide full resolution at the full display rate. My current dual display setup consists of those shown in Figuers 1B and 2, but I did try Fig. 3 and it worked great.
Unfortunately Target Display mode does not work on Thunderbolt iMacs with M1 devices.
forums.macrumors.com
It will work with older iMacs (pre-2011) which support Target Display mode via a mini DisplayPort, which confusingly has the same size and shape connector as Thunderbolt 1/2.
I have a 2011 27 iMac and M1 Mac mini so can confirm this combination does not work.
However, there are some options I’m looking at:
1, Buy a dummy HDMI plug: https://www.amazon.co.uk/dp/B087QDCZ4L/ref=cm_sw_r_cp_awdb_imm_t1_wbY3FbP35W05F?psc=1 - then use VNC (screen sharing) to access the M1 Mac from the iMac.
You can force the 4K dummy HDMI plug to 2560x1440, to match the 2011 iMac resolution. I’ve got one and managed to do this, obviously screen sharing isn’t perfect but a workaround. You can use a USB-C -> DisplayPort or HDMI adapter to get a 2nd monitor connected.
2, Buy a Luna Display USB-C dongle: https://shop.astropad.com/ I’ve ordered one and will give this a go, with the Mac-to-Mac mode. Still waiting on delivery for now.
Again you can use the HDMI port on the mini to connect a 2nd monitor.
3, Extreme but potentially the best option (if you can give up your iMac as a useable computer?): get something like this - https://www.ebay.co.uk/itm/HDMI-DVI...-2560-1440-LM270WQ1-SD-E2-panel-/193390883105
Teardown the iMac and install the driver board to the iMac display. This will give you direct HDMI/DisplayPort/DVI inputs for the iMac display - essentially turning the iMac into a ‘dumb’ monitor - but allowing *any* device to connect and display an image.
These are all workarounds and not ideal - you may find buying a monitor the best option.
Although I’m sorely tempted by those who have made their own 5K iMac monitor - using option 3 with the appropriate 5K screen, driver board and old iMac case. Not cheap - but would give a beautiful 5K monitor.
(Search for ‘Secret Apple 5K display’ - there’s a Reddit thread and YouTube video explaining how it’s done)
EDIT: Removed Reddit 5K monitor info
M1 mini and iMac 2010 target display (mini DP) or 2 23" DVI cinema displays
I have plans for buying an M1 mac mini. My current late 2012 mini is connected to two 23" cinema displays. One via an HDMI to DVI adapter and one via a thunderbolt to DVI adapter. Does the HDMI to DVI adapter plus a new to buy USB-c to DVI adapter work with the M1 mini? I also have an iMac 2010...
forums.macrumors.com
It will work with older iMacs (pre-2011) which support Target Display mode via a mini DisplayPort, which confusingly has the same size and shape connector as Thunderbolt 1/2.
I have a 2011 27 iMac and M1 Mac mini so can confirm this combination does not work.
However, there are some options I’m looking at:
1, Buy a dummy HDMI plug: https://www.amazon.co.uk/dp/B087QDCZ4L/ref=cm_sw_r_cp_awdb_imm_t1_wbY3FbP35W05F?psc=1 - then use VNC (screen sharing) to access the M1 Mac from the iMac.
You can force the 4K dummy HDMI plug to 2560x1440, to match the 2011 iMac resolution. I’ve got one and managed to do this, obviously screen sharing isn’t perfect but a workaround. You can use a USB-C -> DisplayPort or HDMI adapter to get a 2nd monitor connected.
2, Buy a Luna Display USB-C dongle: https://shop.astropad.com/ I’ve ordered one and will give this a go, with the Mac-to-Mac mode. Still waiting on delivery for now.
Again you can use the HDMI port on the mini to connect a 2nd monitor.
3, Extreme but potentially the best option (if you can give up your iMac as a useable computer?): get something like this - https://www.ebay.co.uk/itm/HDMI-DVI...-2560-1440-LM270WQ1-SD-E2-panel-/193390883105
Teardown the iMac and install the driver board to the iMac display. This will give you direct HDMI/DisplayPort/DVI inputs for the iMac display - essentially turning the iMac into a ‘dumb’ monitor - but allowing *any* device to connect and display an image.
These are all workarounds and not ideal - you may find buying a monitor the best option.
Although I’m sorely tempted by those who have made their own 5K iMac monitor - using option 3 with the appropriate 5K screen, driver board and old iMac case. Not cheap - but would give a beautiful 5K monitor.
(Search for ‘Secret Apple 5K display’ - there’s a Reddit thread and YouTube video explaining how it’s done)
EDIT: Removed Reddit 5K monitor info
Last edited:
Any update on this? Curious how I should move forward.Unfortunately Target Display mode does not work on Thunderbolt iMacs with M1 devices.
M1 mini and iMac 2010 target display (mini DP) or 2 23" DVI cinema displays
I have plans for buying an M1 mac mini. My current late 2012 mini is connected to two 23" cinema displays. One via an HDMI to DVI adapter and one via a thunderbolt to DVI adapter. Does the HDMI to DVI adapter plus a new to buy USB-c to DVI adapter work with the M1 mini? I also have an iMac 2010...
It will work with older iMacs (pre-2011) which support Target Display mode via a mini DisplayPort, which confusingly has the same size and shape connector as Thunderbolt 1/2.
I have a 2011 27 iMac and M1 Mac mini so can confirm this combination does not work.
However, there are some options I’m looking at:
1, Buy a dummy HDMI plug: https://www.amazon.co.uk/dp/B087QDCZ4L/ref=cm_sw_r_cp_awdb_imm_t1_wbY3FbP35W05F?psc=1 - then use VNC (screen sharing) to access the M1 Mac from the iMac.
You can force the 4K dummy HDMI plug to 2560x1440, to match the 2011 iMac resolution. I’ve got one and managed to do this, obviously screen sharing isn’t perfect but a workaround. You can use a USB-C -> DisplayPort or HDMI adapter to get a 2nd monitor connected.
2, Buy a Luna Display USB-C dongle: https://shop.astropad.com/ I’ve ordered one and will give this a go, with the Mac-to-Mac mode. Still waiting on delivery for now.
Again you can use the HDMI port on the mini to connect a 2nd monitor.
3, Extreme but potentially the best option (if you can give up your iMac as a useable computer?): get something like this - https://www.ebay.co.uk/itm/HDMI-DVI...-2560-1440-LM270WQ1-SD-E2-panel-/193390883105
Teardown the iMac and install the driver board to the iMac display. This will give you direct HDMI/DisplayPort/DVI inputs for the iMac display - essentially turning the iMac into a ‘dumb’ monitor - but allowing *any* device to connect and display an image.
These are all workarounds and not ideal - you may find buying a monitor the best option.
Although I’m sorely tempted by those who have made their own 5K iMac monitor - using option 3 with the appropriate 5K screen, driver board and old iMac case. Not cheap - but would give a beautiful 5K monitor.
(Search for ‘Secret Apple 5K display’ - there’s a Reddit thread and YouTube video explaining how it’s done)
EDIT: Removed Reddit 5K monitor info
See my update here:
Post in thread 'Connecting Mac mini to iMac as display'
https://forums.macrumors.com/threads/connecting-mac-mini-to-imac-as-display.2269477/post-29468738
Post in thread 'Connecting Mac mini to iMac as display'
https://forums.macrumors.com/threads/connecting-mac-mini-to-imac-as-display.2269477/post-29468738
Oh good idea. I haven‘t tried that But I will. I will try to test that by this time tomorrow (Friday the 29th).
It worked perfectly first time for me. Be aware of two things though:
1) I am using a Late 2009 iMac that had a mini DisplayPort. Newer iMac models have a Thunderbolt port and others have said that does not work. I have no way to verify. Note carefully the symbol designating which port the iMac is equipped with because the physical connector may look identical.
2) This connection will not power your MacBook Air. You’ll need The second USB4/Thunderbolt port for that.
I‘ve included a photo of the specific cable used which has limited availability on Amazon. Your results may vary with other cables.
Attachments
You may be interested in apple’s screen sharing app (though it’s not the same functionality). Then there’s the Luna Display adapter that costs a bit more than cables but could do the job and seems to get good reviews. https://shop.astropad.com/products/luna-displayThank you for testing, unfortunately, the iMac that I have is 2013.
Unfortunately Target Display mode does not work on Thunderbolt iMacs with M1 devices.
M1 mini and iMac 2010 target display (mini DP) or 2 23" DVI cinema displays
I have plans for buying an M1 mac mini. My current late 2012 mini is connected to two 23" cinema displays. One via an HDMI to DVI adapter and one via a thunderbolt to DVI adapter. Does the HDMI to DVI adapter plus a new to buy USB-c to DVI adapter work with the M1 mini? I also have an iMac 2010...
It will work with older iMacs (pre-2011) which support Target Display mode via a mini DisplayPort, which confusingly has the same size and shape connector as Thunderbolt 1/2.
I have a 2011 27 iMac and M1 Mac mini so can confirm this combination does not work.
However, there are some options I’m looking at:
1, Buy a dummy HDMI plug: https://www.amazon.co.uk/dp/B087QDCZ4L/ref=cm_sw_r_cp_awdb_imm_t1_wbY3FbP35W05F?psc=1 - then use VNC (screen sharing) to access the M1 Mac from the iMac.
You can force the 4K dummy HDMI plug to 2560x1440, to match the 2011 iMac resolution. I’ve got one and managed to do this, obviously screen sharing isn’t perfect but a workaround. You can use a USB-C -> DisplayPort or HDMI adapter to get a 2nd monitor connected.
2, Buy a Luna Display USB-C dongle: https://shop.astropad.com/ I’ve ordered one and will give this a go, with the Mac-to-Mac mode. Still waiting on delivery for now.
Again you can use the HDMI port on the mini to connect a 2nd monitor.
3, Extreme but potentially the best option (if you can give up your iMac as a useable computer?): get something like this - https://www.ebay.co.uk/itm/HDMI-DVI...-2560-1440-LM270WQ1-SD-E2-panel-/193390883105
Teardown the iMac and install the driver board to the iMac display. This will give you direct HDMI/DisplayPort/DVI inputs for the iMac display - essentially turning the iMac into a ‘dumb’ monitor - but allowing *any* device to connect and display an image.
These are all workarounds and not ideal - you may find buying a monitor the best option.
Although I’m sorely tempted by those who have made their own 5K iMac monitor - using option 3 with the appropriate 5K screen, driver board and old iMac case. Not cheap - but would give a beautiful 5K monitor.
Deccr,
Hello, did the Luna Display Dongle USB C work for you? I have the same setup as you and wasn’t sure if I should go with option 1 or 2. Thanks
The Luna Display does work well, however I have ended up replacing the iMac with a new monitor.
If you're not sure, you could buy a dummy plug, test it out and return it if you're not happy with it? It's a smaller investment than the Luna Display.
If you're not sure, you could buy a dummy plug, test it out and return it if you're not happy with it? It's a smaller investment than the Luna Display.
I got the screen sharing method to work on the IMac at full resolution when I had the mini plugged into a 4K tv with the HDMI port simultaneously. However when I disconnect the hdmi cable the resolution to the iMac drops and can’t go full screen. Hoping the dummy plug that’s coming tomorrow will fix that. Thanks for the solution, I bought a cheap second hand IMac 27 after reading in several places , Apple included , that it would work as a display only to find it wouldn’t.