Help: Mac mini to Dell Monitor no Output (Issue & temporary workaround)

[soziblewuup]

Hi,

I bought a new Dual Core i7 16GB 1TB Mac Mini a month ago.

All of a sudden (over the last week or so), when booting the machine from off, no display output is sent to my Dell monitor. The Mac Mini itself appears to boot with no issues and is not in sleep mode. The monitor just insists there is no signal sent from my Computer.

For the last few days I assumed this was an issue with the Dell monitor itself as they are prone to issues with receiving a display signal. However, I recently hooked the display to a Surface Pro for testing purposes and I had no issues (using the same Displayport to Mini Displayport cable).

I tried everything, including hard rebooting the Mac Mini to no avail. As a last ditch attempt I made up my own reboot method (which I believe probably isn't to healthy for the Mac Mini): Whilst the Mac Mini is on I hold down the power button for 15 - 20 seconds and releas. I then continuously tap the power button which fires up the Mac Mini and cuts the power roughly 3 seconds into the boot. I then press the button once to reboot for a final time and by some miracle the Mac Mini sends a signal to my display. I now have to repeat this process every morning to get the display to fire up.

Does anyone know why this could be happening?
And what is it about my very random boot method that seems to revive the display output, when a normal reboot won't?
Finally, I'm assuming doing this everyday will have some kind of negative impact on the Mac Mini?

Thanks all!

 

[itsOver9000]

Have you tried NVRAM reset?

Resetting NVRAM

1. Shut down your Mac.
2. Locate the following keys on the keyboard: Command (⌘), Option, P, and R.
3. Turn on your Mac.
4. Press and hold the Command-Option-P-R keys immediately after you hear the startup sound.
5. Hold these keys until the computer restarts and you hear the startup sound for a second time.
6. Release the keys.

 

[soziblewuup]

Hi itsOver9000,

I just tried that and it worked when I used the key combination. However, rebooting (as standard) after the reset leaves me with the same problem. Thanks for the response.
[doublepost=1475503600][/doublepost]I just tested the Display with a Macbook Pro and no issues there either. With the Mac Mini the Dell detects there's some kind of input as the display wakes and says "entering sleep mode". Still requires the reboot method outlined above (or a NVRAM reset) to get it up and running. All subsequent shut downs and reboots have the same issue.

 

[Fishrrman]

Random thoughts...

Try a different connecting cable. This might make all the difference.

Boot Mac with monitor OFF.
After bootup sound, turn monitor ON.
Any change?

If you're booting the Mac with monitor power on, and no display, try turning the display OFF and then ON again.

Did I mention to try a DIFFERENT connecting cable?

 

[soziblewuup]

I've tried all of the Monitor off / on Mac off / on configurations outlined. I haven't tried a different cable. I'll have to go and buy one. Certainly seems unusual that the cable would be at fault when two other devices work flawlessly with it. However, I won't discount it and will give that a try. Thanks for the response.
[doublepost=1475505247][/doublepost]New cable ordered.

 

[294307]

I've had issues with the Mac mini and Dell monitors before when connected via the Thunderbolt port (and even over HDMI with other monitors sometimes, but rarely). Sometimes a picture will be displayed, other times not at all and requiring a hard reset. In some cases unplugging the cable and plugging it back in works, other times only a PRAM reset did anything. Hopefully you can see where I am going when I say I couldn't find out the cause, but the only thing I do know is it only happens on the Mac mini. I do remember reading somewhere that this kind of issue can also be caused by the GPU being disabled when a display isn't plugged in to the Thunderbolt/HDMI port when the Mac is initially booted, but I'd have thought that would only apply to discrete GPUs in older Mac minis, but who knows. Just something to bear in mind, I can't confirm for sure.

Do you have FileVault enabled? If you do that is known to cause issues displaying a picture on an external display until you have decrypted the drive on boot. If you have it enabled, perhaps investigate whether that exacerbates the issue or is the actual cause. I'm not suggesting you should disable it, but it might be worth investigating to see if it's the cause.

 

[soziblewuup]

I've had issues with the Mac mini and Dell monitors before when connected via the Thunderbolt port (and even over HDMI with other monitors sometimes, but rarely). Sometimes a picture will be displayed, other times not at all and requiring a hard reset. In some cases unplugging the cable and plugging it back in works, other times only a PRAM reset did anything. Hopefully you can see where I am going when I say I couldn't find out the cause, but the only thing I do know is it only happens on the Mac mini. I do remember reading somewhere that this kind of issue can also be caused by the GPU being disabled when a display isn't plugged in to the Thunderbolt/HDMI port when the Mac is initially booted, but I'd have thought that would only apply to discrete GPUs in older Mac minis, but who knows. Just something to bear in mind, I can't confirm for sure.

Do you have FileVault enabled? If you do that is known to cause issues displaying a picture on an external display until you have decrypted the drive on boot. If you have it enabled, perhaps investigate whether that exacerbates the issue or is the actual cause. I'm not suggesting you should disable it, but it might be worth investigating to see if it's the cause.

Appreciate the response. I'll check tonight if FileVault is enabled and get back to you. Should also receive my new cable today so will give everything a test and post the results.

 

[294307]

Appreciate the response. I'll check tonight if FileVault is enabled and get back to you. Should also receive my new cable today so will give everything a test and post the results.

If you can't recall enabling FileVault or if your machine is set to automatically login to your user account on boot, then you won't have it enabled, as it is not turned on by default. You can check by going to System Preferences -> Security & Privacy -> FileVault.

 

[zootalaws]

I had a similar problem with a 2012 Mini and a Samsung 24" monitor.

I pulled the hdmi to plug into my Raspberry Pi to follow the boot. When I plugged it back into the mini, no video. During boot I didn't get the Apple logo, so I was pretty sure it wasn't OS config, but suspected it had changed output and couldn't sync back to the Samsung.

A few hard resets, reset PRAM, etc. And no luck.

Went to bed.

In the morning I tried everything I could think of, including ssh and remote control, but nada.

I was confident in the hdmi cable - it has worked fine on the Mini for a year, works fine on the Pi, but I went and raided the TV anyway and... voila.

Wasted a bunch of hours 'knowing' I had a good cable.

 

[mike_r_c]

I have the exact same problem with a Mac Mini it worked fine for years. Did a fresh install of 10.13.6 and then this problem began. (Booted from usb, erased and encrypted ssd, then installed 10.13.6)

Swapping dell displays, swaped display port cables and even swaped to HDMI does not fix the problem.

The Mac simply now requires a hard power cycle after forst boot to get a display.

Mac mini late 2014, intel iris graphics card.