USB C to Thunderbolt Not working with Mini Monitor.

Hi everyone,

I just got a new iMac with USB C and the Mini Monitor isn't working. The mini monitor has Thunderbolt of course and I have Apple's USB C to Thunderbolt adapter plugging it in. I'm getting nothing, system isn't even seeing it. From what I've already researched this is supposed to work. I have the latest version of Mojave installed as well as the newest Resolve update that came out today- 15.2.4 Studio. (though it wasn't working with previous version either) Can someone help? Thanks!

I bet this is a Desktop Video issue. Have you installed the latest version of Desktop Video?

Beyond that, I think this will require a call to BMD Support in order to get it fixed.

I wonder if it has something to do with power supply. The Mini Monitor is using quite some, and if you have other devices plugged in, that might be a problem.
I'm using the Mini Monitor successfully with an adapter from AKiTiO, the T3T. Can't comment on Apple's one.

[Dwaine Maggart]

If it's not showing up in System Report - Hardware - Thunderbolt, it would not be a Desktop Video issue.

Are you sure you have a proper Thunderbolt 2 cable between the adapter and the Mini Monitor, and not a mini-Display port cable?

Is the LED on the Mini Monitor, near the TBolt port, lighting up?

If it's not showing up in System Report - Hardware - Thunderbolt, it would not be a Desktop Video issue.

Are you sure you have a proper Thunderbolt 2 cable between the adapter and the Mini Monitor, and not a mini-Display port cable?

Is the LED on the Mini Monitor, near the TBolt port, lighting up?

Hi Dwaine,

Thanks for your help! The mini monitor is NOT lighting up and under System Report it says 'No device connected'. As far as a thunderbolt cable, I believe so... it has a thunderbolt icon and it's the Apple cable. The mini monitor does work when I plug it into my Macbook Pro using this cable.

Should I re-install Desktop Video?

I bet this is a Desktop Video issue. Have you installed the latest version of Desktop Video?

Beyond that, I think this will require a call to BMD Support in order to get it fixed.

Yep, I have installed the latest version of Desktop Video and restarted.... will try to reinstall...

If it's not showing up in System Report - Hardware - Thunderbolt, it would not be a Desktop Video issue.

Are you sure you have a proper Thunderbolt 2 cable between the adapter and the Mini Monitor, and not a mini-Display port cable?

Is the LED on the Mini Monitor, near the TBolt port, lighting up?

Hi Dwaine,

Still no luck. Anything you think I should try? I've tried re-installing Desktop video a few times and nothing is helping. Have even tried plugging in other things into the ports on the off chance the port wasn't working but external drives, etc work fine. Thanks!

[Dwaine Maggart]

I just went an hooked one up as a sanity check to an iMac with TB3 ports. Using the Apple TB2 to TB3 adapter. Works as expected.

You say the Mini-Monitor and it's Tbolt 2 cable works when you plug it into a MBP. A Tbolt 2 MBP, I assume?

If the Mini Monitor and it's TB2 cable are known good, all that leaves is a bad TB3 to TB2 adapter, or the port you are plugging the adapter into is not a TB3 port.

The Mini Monitor should light up. That's independent of Desktop Video drivers. if it's not lighting up, its not getting power from the chain of stuff its connected to.

Make sure your TB2 to TB3 adapter is really the Apple adapter. Other vendors adapters may not work to provide power.

I just went an hooked one up as a sanity check to an iMac with TB3 ports. Using the Apple TB2 to TB3 adapter. Works as expected.

You say the Mini-Monitor and it's Tbolt 2 cable works when you plug it into a MBP. A Tbolt 2 MBP, I assume?

If the Mini Monitor and it's TB2 cable are known good, all that leaves is a bad TB3 to TB2 adapter, or the port you are plugging the adapter into is not a TB3 port.

The Mini Monitor should light up. That's independent of Desktop Video drivers. if it's not lighting up, its not getting power from the chain of stuff its connected to.

Make sure your TB2 to TB3 adapter is really the Apple adapter. Other vendors adapters may not work to provide power.

Great info, thanks!

Yes, the cable works with my 15" Macbook Pro w/ thunderbolt 2.

The port is definitely TB3.

I bought the adapter at adorama so am confident its a real apple adapter.

I guess I'll test the adapter to see if it has issues. Thanks!

Alright so here's the culprit: This was a new mac and I took it to get a RAM upgrade. The technician didn't seat the ports correctly when closing up the machine. I took it back and he reseated it and now it clicks beautifully when I slide the USB C adapter and everything is working! Thanks again for all the help!

[Dwaine Maggart]

Thanks for reporting the solution!

I am actually still having an issue with getting dual monitor to show up in Davinci resolve 15.

On my last system, I had TB2, and it worked fine. On the new 2019 iMac and TB3 adapter, it is not giving me the option to use dual screen.


The light on the Mini Monitor is on.
Blackmagic Desktop Video is recognizing the Mini Monitor.
Apple does not recognize a second display (if that matters)
The Ultrastudio Mini Monitor is juicing a 25 foot HDMI cable.

Yet, Davinci Resolve 15's "dual" monitor layout option is still greyed out and non-selectable.

I didn't install any drivers, just the Desktop Video software.

[Dwaine Maggart]

The Mini Monitor has nothing to do with dual screen mode. Dual screen more requires 2 GUI displays to be connected.

Thank you Dwaine. That sorted it out for me. I was thrown of by “dual”. It is working now. I just had to save and quit resolve, and the reopen it to get playback running. I thought i could just turn on playback through the mini monitor, but it required restarting. All is well, and yes, the Apple t2 to t3 adapter works!