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Mac mini doesn't display an image on startup when using USB-C to DisplayPort

I know this is not a fix but a work around. I have the same issue using FV and mini or 2017 MBP to eGPU, egpu to monitor. On power up I wait 30-40 seconds then blind type my password. It has worked every time. But yes this should not be the norm.

When I tried a hdmi from the mini to the monitor and a hdmi from the egpu to the monitor it ended up being a nightmare trying to switch between the 2. It was not consistent and had trouble going back to the egpu.

I gave and up pulled out the mini cable, just using egpu and blind password works for me. It is the same on my 2017 MBP as the 2018 mini using the same setup.
 
wdh_2019 said:
They just asked me to send them a "disk image" so the engineers can help identify the issue. I'm not optimistic they'll find anything. They said it will take 2 days....well 2 days later still waiting. Meanwhile I have ~3 more days to decide if I should return the mini and just go with another MBP. Problem is I don't need another laptop right now and it's 1K more to get same specs. Frustrating.
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This is exactly what they wanted from me. Then they wanted me to send in the mac mini and thats when I returned mine. Didnt need that.
 
IngerMan said:
I know this is not a fix but a work around. I have the same issue using FV and mini or 2017 MBP to eGPU, egpu to monitor. On power up I wait 30-40 seconds then blind type my password. It has worked every time. But yes this should not be the norm.

When I tried a hdmi from the mini to the monitor and a hdmi from the egpu to the monitor it ended up being a nightmare trying to switch between the 2. It was not consistent and had trouble going back to the egpu.

I gave and up pulled out the mini cable, just using egpu and blind password works for me. It is the same on my 2017 MBP as the 2018 mini using the same setup.
Click to expand...



That's interesting so happens on MBP too...is that only when connected to eGPU? I never had the problem with my MBP. It's just odd that it happens more with the mini, but I never tried to blind type password.....maybe I'll try that to see what happens. As you said not a fix and also not acceptable for a brand new computer. I also wonder why this is only happening to some? I did a wipe and fresh install of OS...and now on the second mini with same problem. If it's a problem with T2 chip or FV, why aren't more Macs affected? I tried HDMI to HDMI and had same problem, so not just USB-C for me.
 
wdh_2019 said:
That's interesting so happens on MBP too...is that only when connected to eGPU? I never had the problem with my MBP. It's just odd that it happens more with the mini, but I never tried to blind type password.....maybe I'll try that to see what happens. As you said not a fix and also not acceptable for a brand new computer. I also wonder why this is only happening to some? I did a wipe and fresh install of OS...and now on the second mini with same problem. If it's a problem with T2 chip or FV, why aren't more Macs affected? I tried HDMI to HDMI and had same problem, so not just USB-C for me.
Click to expand...

Yes that’s when connected to the eGPU. The entire problem is FV related, not T2.
 
Just heard back from engineering. They asked to wipe and reinstall OS as a fresh Mac, turn FV on, and see if problem still occurs. I'm guessing that they have enough returned Mac minis to try this themselves, and in the end it still means I can't turn on FV (at least with my own files on the Mac).
[doublepost=1551465395][/doublepost]I also must have tried this before. But I reinstalled OS so many times, I cannot recall if I turned FV off and on with the same fresh install to see what happens...
 
Bumping an old thread, but I've been experiencing the same on a 2018 Mac mini. It comes and goes, and at times I have to switch between hdmi-hdmi cable and USB-C to DisplayPort cable to get a picture to show on my monitor (Dell U2718Q 4K). Recently the DisplayPort connection wouldn't work at all, so I left it on HDMI (which is definitely fuzzier compared to DisplayPort).

And now, today after updating to 10.15, I can't get either cable connection to show something on the display. Even after power cycling everything, rebooting the Mac mini, even erasing the Mac mini!

This has gotten painful. I'm going to give in and replace it with 5K iMac.
 
Just came on here to start a similar thread and this one was on the front page. I was tearing my hair out as I've never seen anything like it and its so random that for the first while I wasn't sure if it was my monitor or Mac Mini which was at fault.

I'm also using an LG 4K monitor - 27UD88Q.

I'll try ordering the usb-c to DP cable linked above and see if that helps and in the meantime log a call with Apple Support I guess.
 
This is an old thread, have the recent posters updated to Catalina? That is causing issues with some USB-C to HDMI/DP cables.
 
I have updated to Catalina. Though I was experiencing issues even before that.

However, I tried a 23” 1920x1080 monitor and it works fine over multiple connections types (HDMI to HDMI and usbc to displayport). But no go on my 4K monitor.
 
This is a bit off topic but same general subject.

Mac Mini 2018
Newish Dell P2415Q 4k monitor
HDMI to HDMI high-speed cable.

Everything worked fine under Mojave. I installed Catalina and the monitor received no signal from the computer. I went back to Mojave and still no signal (just a black screen).

I tried everything including a different high speed hdmi cable but nothing worked. Finally I switched the monitor into HDMI 1.4 only mode and everything works 100 percent of the time ( but at 1080p 30 hz).

I've got a DP to usb-c cable arriving today and hopefully that will allow me to go back to 4K at 60 hz.

EDIT: The DP to usb-c cable got here and everything works great. System information shows the following just as I want; no more blank screen on startup; and sleep works also.

Resolution: 3840 x 2160 (2160p 4K UHD - Ultra High Definition)

UI Looks like: 1920 x 1080 @ 60 Hz
 
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Well, I wiped the Mac mini clean, set it up using HDMI with an older monitor. All worked well.

Connected it to the 4K display and neither connection worked (HDMI nor USB-C to DisplayPort). I have 2-3 DisplayPort cables but maybe they’re the issue. This is really disappointing.
 
I got DP to USB-C and they are not working either, only the HDMI to HDMI work. Something odd going on, and it's related to Catalina as Mojave is fine. May be driver related.
 
So having both monitors working fine with USB-C to DP I disconnected one and plugged in a USB-C to HDMI cable and ok, it worked! So I changed the other monitor as well and neither worked...

Totally confused. It would be fine if it was not for the fact I want my PC using the DP connection and the Mac using the HDMI. The fact I got one monitor working proves that the cables do work and again, only been an issue since Catalina and I note on the Apple communities many are complaining about this.
 
Yeah, its definitely an odd problem. I experienced it under Mojave but usually could get it working after power cycling monitor and the Mac mini a few times.

Now with Catalina I can only get a picture on my 1080p display (with either cable type), but on a 4K display I can’t get anything.
 
I’ve had this problem with Mojave and an LG 4K monitor over USB-C to display port. The monitor aggressively turns off for power saving (even when I lock the Mac to login screen), and the Mac frequently wouldn’t power on the display when I came back to it. After the latest update (supplemental update 2?) is been much better.

My strategy when it didn’t turn back on was to force the monitor to go back to sleep by going back to the lock screen (my Apple Watch was unlocking the Mac so I memorized the keyboard shortcut). After 2 out 3 times of that it’d finally work.

this thread has me scared to update to Catalina ... but it is kind of the reason I came here: to see if things were safe...
 
profets said:
I experienced it under Mojave but usually could get it working after power cycling monitor and the Mac mini a few times.
Click to expand...

The occasional issue I had on Mojave was that only one monitor would come on but it was an easy fix by just reinserting the USB-C for the other monitor and that was that. Getting annoyed with this now!
 
My usb-c to DP cable arrived today and doesn't make a difference. I couldn't get a picture on the 4K monitor with HDMI or any usb-c combo.

I connected an old monitor via HDMI and got a picture to come up. I was then able to plug the new monitor in to the Mac mini with HDMI and it works. Its almost as if the Mini needs a non-4K monitor to kick the video feed in to life, then you can switch to a 4K one and get a picture just fine.

I'll open a support chat with Apple, but its a really strange one.
 
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Have just spent over an hour on the phone with Apple support. They are saying the monitor is not compatible with a Mac mini - the only monitor which is guaranteed to work is the LG Ultrafine 4K which obviously is the one they sell at the Apple Store.

My Mac mini is 6 weeks old... their advice is to wait to see if future OS upgrades fix it.

The engineer was very helpful, but his advice was to sell the Mac Mini.

He did ask for an exception to the 14 days thing so I could return it but they won't do it.

Any ideas?

I can't even reject the goods as faulty because to do that you have to have given them a chance to repair them. And they don't think there's anything wrong with it...
 
Have you tried to reset the SMC and NVRAM of the Mini?

I am also running an LG monitor and have had connectivity problems since first using on Mojave. Everytime I have gotten it running again.
 
Yip, have tried all the usual things. Sometimes it will work for a few days without any issue at all, will wake from sleep first time, every time. Some days I have to power it off, connect an old monitor, start it booting and then swap it back.

Apple are aware of the issue which is fine, but telling people to just wait for the next version of OS which might fix it isn't a great answer. Especially as they've just released a major update and its not done anything.

Besides, its not like a reliable display is a minor part of using a computer.
 
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Have spent another hour on the phone with a very helpful Mac tech this morning, have tried loads of things and are no further forward. He's stumped too but will be back in touch next week.
 
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