No HDMI signal and target disk mode does not work after screen broken

I bought this MacBook Retina 2015 with a broken screen. I can see the backlight come on but the screen is broken. However I connect a Satechi USB-C mulitadapter and get no HDMI signal. This adapter works fine on another similar machine. I can hear it recognize charging when I plug in a power adapter. But I am also not able to get the mac in Target Disk Mode. I can see traces of the bouncing USB logo so it must be in TD mode. But I need to get to the disk or get a video signal in some way to check the mac.

Any ideas why USB-C is not working with HDMI adapter or TD mode but seems to charge?


It seems that all USB-C MacBook systems support TDM with these 2 cables:

  • USB-C to USB-A. It must be the USB-3 and not USB-2 version cable. You can see if a cable is USB-3 by the 5 pins inside the connector. USB-2 only has 4 pins.

Block Image

Here's Apples cable: Belkin USB-A to USB-C Cable (USB 3.1) I managed to get a cheap one that works fine.

  • USB-C to USB-C cable. Apple calls it Thunderbolt 3 but as long as it is "data cable" and not the supplied "charging cable" it should work fine.

Here's Apples cable: Thunderbolt 3 (USB‑C) Cable (0.8 m). I managed to get a cheap one at the local gadget shop that worked fine.

I tested both these cables with TDM and the working MacBook 12" Retina. Works like a charm. But this MacBook has a broken screen and does not work with TDM. I guess I will have to get a new screen and will update!

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Are you connecting between two USB-C systems and connecting directly with the cable (no hub)? You'll need to do that for Target Disk Mode on this system.


I have the same year MacBook Retina 12" here that I tested with and HDMI works fine with the Satechi adapter. I see now that Target Disk Mode does not work when I use a USB-C to USB-2 cable. I thought it would show up but only be slow. I guess it is just a charging cable. So I need a USB-C to USB-C data cable? But any ideas why there is not HDMI signal? Does the HDMI signal need the OS to load? Since I have no idea what state the drive is in now, it may not even have a working OS. I guess the adapter just works but maybe the Macbook needs to load drivers for external monitor? My guess?


Sadly, you need a straight USB-C to USB-C cable to do Target Disk Mode (no adapters).

Yes, the OS needs to load as the drivers need to be loaded. So not having the OS running would explain that.


The only risk here is you need to have a USB-3 system as a USB-2 system can't access the extra lines. I had forgotten this also works!


I wonder if something is wrong with the SSD since i can see the floating USB symbol on TDM but no response on the USB part. I even tested a sertified USB-C to USB-C cable. My other MBP 12" works fine in TDM. This with the broken screen, no reponse. So waiting for a new screen then. Hope to update then.