More HDMI-DVI Issues on Mac Mini

Ocnetgeek

macrumors newbie
Original poster
Sep 1, 2018
24
4
Oak Creek, WI
Ordered a new Mac Mini last week and was really looking forward to using it. I think I am going to send it back though since it won't work with my existing monitors. I have three older Dell Monitors running 1680 x 1050 and that works for both my Macbook Pro and Work Laptop. Received my new Mac Mini today and plugged it into my KVM just like I have for several Macbook Pro and Mac Pro systems in the past. Pressed the power button and waited and my display showed me an error message that it could not display that video mode. I thought that this was just a Catalina issue and connected the HDMI port on my Mac Mini to a TV and could see the display ok. Used that to reboot into recovery mode and downgraded the Mac Mini to Mojave and have the same issue. When booting with display attached to my KVM and Older Monitor I cannot see the screen at all. Kind of bummed that they have changed something in the hardware on the Mac Mini that has worked on my current setup for years. Not ready to ditch my current monitor setup and really don't want to have to fuss with connecting to another device to get the login screen every time I reboot.
 

getrealbro

macrumors 6502
Sep 25, 2015
378
130
I had a similar problem with my 2018 Mini and a DELL2407WFP when I used the HDMI to DVI cable that worked fine with my 2014 Mini. In my case I simply purchased a USBc -> DVI cable and the DELL2407WPF is working just fine now.

GetRealBro
 

Ocnetgeek

macrumors newbie
Original poster
Sep 1, 2018
24
4
Oak Creek, WI
Ordered an adapter and will see how that works. its kind of frustrating that it’s inconsistent. Booted with the monitor disconnected and typed password in blind and then plugged in the monitor after that and was able to see the desktop. Then rebooted to install new software and was able to login without disconnecting again.
 

Dameatball

macrumors regular
Feb 7, 2014
114
47
San Francisco
My understanding is it is a Catalina issue but it’s firmware. I’d research it but I believe you have to delete/wipe it clean and then install Mojave.

I bought my mini with Mojave and never had an issue with display-both running an egpu and direct to a monitor via hdmi. Once I upgraded the display is a total disaster.
 
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getrealbro

macrumors 6502
Sep 25, 2015
378
130
The 2018 Mini boot process is a little quirky.

In the case of the two monitors on my mini, it always begins booting using the DELL monitor attached via USBc, even though that monitor will not end up with the macOS menu or dock. Then part way through the boot process, both monitors go black and it switches to the BENQ monitor attached via HDMI to complete to boot. IOW it appears that my 2018 Mini treats HDMI as a 2nd class port during booting.

You may be seeing something similar with your DELL connected via HDMI.

GetRealBro
 

Fishrrman

macrumors P6
Feb 20, 2009
18,199
6,076
The "black display at boot" problem with the 2018 Mini seems to be aggravated by:
- which make and model of display(s) you have
- which connection scheme you're using (HDMI, DVI, USBc, etc.)
- which cable you're using

Having a KVM switch "in the mix" almost certainly will make matters worse.

Your choices:
1. Find a connection scheme that works for you.
2. Send the Mini back.
 

Codeseven

macrumors 6502a
Dec 31, 2008
777
300
Ordered a new Mac Mini last week and was really looking forward to using it. I think I am going to send it back though since it won't work with my existing monitors. I have three older Dell Monitors running 1680 x 1050 and that works for both my Macbook Pro and Work Laptop. Received my new Mac Mini today and plugged it into my KVM just like I have for several Macbook Pro and Mac Pro systems in the past. Pressed the power button and waited and my display showed me an error message that it could not display that video mode. I thought that this was just a Catalina issue and connected the HDMI port on my Mac Mini to a TV and could see the display ok. Used that to reboot into recovery mode and downgraded the Mac Mini to Mojave and have the same issue. When booting with display attached to my KVM and Older Monitor I cannot see the screen at all. Kind of bummed that they have changed something in the hardware on the Mac Mini that has worked on my current setup for years. Not ready to ditch my current monitor setup and really don't want to have to fuss with connecting to another device to get the login screen every time I reboot.
Uhg! Just saw this. I was just asking in another thread if I should bother to update my still in the box Mac Mini to Catalina (I’m assuming it’s shipped with Mojave) now I see this. I too have an older DELL 2005 1680x1050 DVI-D (Dual Link) monitor that I assumed would be plugged into the HDMI port, like it has been on my old MBP. Did I just order the wrong cable (HDMI 2.0 to DVI-D) but instead should have ordered a USB (C or B ?) to DVI-D cable?

EDIT: Ordered the recommended cable in this thread....should be fine.

https://forums.macrumors.com/threads/connect-two-dvi-d-1280-1024-monitors.2173508/
 
Last edited:

Dameatball

macrumors regular
Feb 7, 2014
114
47
San Francisco
Just a guess but the egpu issue with Catalina and the mini requires you to boot up the Mac first, wait a minute then turn on or plug into the egpu. Maybe it’s the same with the op issue? I’d try a different adapter/connection port if possible as well.

That said I don’t have any issues booting up directly via hdmi to a monitor, only when the egpu is plugged in at boot do I get the black screen.

Best thing to do is totally erase the mini and restore it to its factory settings with the original OS (if Mojave) until the issue is fixed.