olaf261 Author

Level 1

5 points

Display not detected on DVI or HDMI. VGA works.

DVI and HDMI are usable in windows, along with VGA. Holding (option) also shows the boot loader menu on HDMI, DVI and VGA. The Apple logo and boot screen progress bar appears in DVI, HDMI and VGA too.
but when the MAC OS session starts, all DVI and HDMI displays turn off.
a VGA cable must be connected to the display in order for the Mac to detect it. The Mac won’t detect a HDMI or DVI display at all
Ive tried resetting NVRAM, safe mode, internet repair.

How can the OS be restored so that the DVI/HDMI displays persist once the OSX session starts?

Mac Pro, OS X 10.10

Posted on Oct 28, 2020 4:02 PM

Top-ranking reply

Grant Bennet-Alder

Level 10

140,927 points

Posted on Nov 6, 2020 5:53 PM

How to reinstall macOS from macOS Recovery - Apple Support

The other way is to make your own Boot Disc, except not on a disc, on a 16GB USB stick. This BOOTAble device, once made, can be used to install again later without having to endure another download:

How to create a bootable installer for macOS - Apple Support

TIP: if you name that USB stick exactly MyVolume, you can copy and paste the command from the article directly to the Terminal command line, without error-prone editing.

Tip: the 30 minutes it takes to manufacture the USB stick provides far too little progress reporting, and will feel like an eternity.

View in context

Similar questions

21 replies

olaf261 Author

Level 1

5 points

Nov 11, 2020 8:51 PM in response to olaf261

Johnb-one

Level 6

9,180 points

Oct 29, 2020 9:51 AM in response to olaf261

Thanks,olaf261. That helps us a bunch. I’d either suspect the adapter you’re using, here i’m guessing an Apple Multiport av adapter, see if you can turn off displayport 1.2 on the monitors themselves and reset the monitors . Your mac pro 6.1 (cylinder model) supports thunderbolt 3 i think, which supports mini display port natively, and vga/hdmi with adapters-and regular displayport too, with the ability to use a usb-c monitor. You have tried safe mode + internet recovery, so that’s out. You could try regular recovery ( hold down apple(command/cloverleaf) +R keys on reboot. You should see the startup manager and from there pick the drive with the recovery partition. Then you can re-install the OS. The other way would be make a bootable usb stick/flash drive with the OS on it, then holding down ‘option’ while starting up and plugging in the usb stick might let you do that. Otherwise, after doing the reset smc/pmu , reboot and hold down the “D” key which should get you to Apple Diagnostics -which runs some basic tests and checks stuff out. If that doesnt do anything...... and the reset smc/pmu or OS re-install does nothing to fix it, then i’d suspect your video cards might be bad. I don’t know if Apple still has a recall/repair program for them anymore. You might want to check it out and see if it’s still running.

good luk to you, olaf261

John B

Oct 29, 2020 7:08 PM in response to olaf261

In one of the posts you have scattered all over the place you show a displays preferences of your VGA display. The NAME of that window is the name of the display, obtained from the query and response over the EDID leads.

As I said somewhere else, Windows pays not the slightest bit of attention to what EDID returns.

Perhaps your display has forgotten how to respond to the EDID query when using other than VGA?

olaf261 Author

Level 1

5 points

Oct 31, 2020 12:31 AM in response to Grant Bennet-Alder

Re. Grant: “forgotten how to respond to EDID” interesting idea. Does the Apple boot- loader, Apple boot-status-bar and diagnostic test (on+ Option D) rely on EDID to establish a connection to the monitor? Below I show the Option D test results find no errors on a DVI connected display.

It is a rather big hassle to re-I stall my OSX but willing to give it a go if the general consensus is that we have a software error on our hands.

Re. DVI-D EDID on the monitor: I could connect the monitor to another Mac (late 2014 MBP). I will report back with findings.

olaf261 Author

Level 1

5 points

Nov 11, 2020 9:05 PM in response to Grant Bennet-Alder

Grant said I must install the version that is installed already - which is 10.10.5 And following on from the other post- recovery partition is crashing- panic: CPU0.... and lots of numbers.

So the link posted on how to create a USB bootable only show links to later OSX’s.

I therefore made a 10.10.5 bootable using the methods described at macworld.co.uk

The installer is failing: Undefined error 0.

So I am stuck. Can I safely install a later OS? Or will this result in a clean install rather than a “install over the top”.

the end goal is simply to restore EDID comms on DVI.

olaf261 Author

Level 1

5 points

Nov 11, 2020 8:54 PM in response to olaf261

I will recreate the install USB. Using the method posted by grant above and try again.

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

Display not detected on DVI or HDMI. VGA works.