Monitor causes Mac Pro 2013 not to boot

Question

Level 1

9 points

Monitor causes Mac Pro 2013 not to boot

I have a Dell P2715Q 4K monitor attached to my Mac Pro 2013 (8-core, D300's, 64gb RAM), which appears to be not allowing the Mac Pro to boot properly(?).

It has been working perfectly fine for about a year, but when I logged in this morning, the mouse appeared not to be working, so I managed to use the keyboard to shut down the Mac Pro normally. Upon reboot, problems arose.

Here's what it's doing exactly:

1) I turn on the Monitor, then the Mac (or visa verse);

2) I hear the 'ta-da' after BIOS post;

3) Monitor immediately goes into 'power save' mode (whatever the correct wording is), but I never see the Apple logo or anything else;

4) I get a blue light if I hit the caps lock on the keyboard;

5) Back of Mac will alight during movement, as it should;

6) Cannot log in remotely, though. I normally can;

7) I forcibly shut down the Mac (holding the power button for multiple seconds), and repeat a few times.

Okay, I drag out an older 1080p monitor, to see if the problem is the monitor. Here's what happened:

1) Monitor works this time, but displays 'no entry' symbol;

2) I boot up with macOS USB flash install drive;

3) I tell it to boot up from my primary (internal) SSD drive

4) I do lots of tests with Disk Utility and TechTool Pro -- all good (disks, RAM, processors, sensors, etc)

5) I reboot multiple times, just fine;

6) I conclude that this problem is because I forcibly shut down the Mac multiple times, probably nothing wrong with the principal SSD or any of the Mac components.

Okay, I re-attach the Dell P2715Q 4K monitor, thinking maybe it's all a fluke. Here's what happens:

1) Same as before, I hear the 'ta-da' after boot;

2) Monitor immediately goes into power save mode (no Apple logo, or anything else);

3) Mac otherwise responsive, but cannot log in remotely, just as earlier before.

I re-attach the older 1080p monitor again, and everything is just fine.

I've never heard of a monitor not allowing a computer to boot properly. Is the monitor sending some kind of signal to immediately go into sleep mode? Note that I do not have any sleep mode turned on on my Mac, as mine typically runs 24 hours a day, as a server.

Are there any known problems with 4K monitors, or specifically the Dell P2715Q (or P2415Q), that disallow the computer for booting?

Any suggestions?

Mac Pro (Late 2013), macOS Sierra (10.12.4)

Posted on Apr 23, 2017 1:20 PM

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Answer 1

mk553 Author

Level 1

9 points

Apr 29, 2017 4:13 PM in response to DonH49

Thanks, that's interesting. Tried those suggestions to no avail, but found this thread:

Blank screen after upgrading Mac Mini to macOS Sierra 10.12.4

It seems it's becoming a known issue on the 10.12.4 update. I had also updated mine about a week before (I never reboot or shutdown, so that's probably why I didn't put that two-and-two together).

I've submitted the possible bug on Apple's feedback page. Hopefully the next release will take care of it, otherwise, in the meantime I guess I'll roll back to 10.12.3...

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Answer 2

DonH49

Level 6

16,704 points

Apr 24, 2017 4:37 AM in response to mk553

its all normal stuff. Unexceptable but that's the way it is. Separate your displays on each bus. AND do not have on the same bus but other thunderbolt port any bootable devices. Try to keep those to their own thunderbolt bus. Experiment around with the TB bus and ports and eventually you'll find a combo which works. Do not just assume you can attach whatever to where ever especially bootable drives. Even connecting non bootable drive to a port on the same bus as a Display will cause issues. It seems that daisy chaining is a better method but not with a display in the chain, especially 4k or higher displays.

Now there will most likely be others who think this is non sense but it does not matter to me because it took me better part of two years but I currently have all many many externals acting as I would expect with any sort of problems. Yes I can duplicate many of the "other" problems if I connected my externals in a different manner.

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Answer 3

dot.com

Level 4

2,449 points

Apr 30, 2017 12:44 PM in response to mk553

Try booting into single-user mode with the Dell monitor and carefully watch the screen for any errors or messages that might give a clue to what the problem is. Use Command+s for single user mode. At the end of the single-user bootup process, and there is no clues printed out, you type the word "exit" (without quotes) to continue to the GUI login - you will see more messages that might have a clue so watch carefully. You might need to use a camera to record a video of the process as there are a lot of messages that get printed out quickly.

I don't know for certain, but would certainly guess that a bad monitor could prevent system from booting completely if the video board notices a problem during boutup which might prevent completing the boutup process. Sounds like this is your situation, since you can't get network access (so network interfaces not comletely setup).

Why not boot up with both monitors attached and see what happens? Have the older monitor as your primary and the Dell as the secondary monitor. Primary interface is gonna be the one that works correctly with the older monitor. After system boots up you can do a lot more to diagnose the problem, like see what System Information sees for the displays and what System Preferences Displays shows.

Good luck...

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Answer 4

mk553 Author

Level 1

9 points

Apr 30, 2017 1:42 PM in response to dot.com

Thanks for the suggestions, dot.com.

So far, I rolled back to macOS Sierra 10.12.3, which was helpful, but not a fix. It lets me occasionally log in after a reboot, but at least I always see the Apple logo.

I tried similar instructions to yours at: https://community.spiceworks.com/how_to/82502-mac-mac-boots-to-a-black-screen-wi th-cursor

The boot text didn't show anything interesting, as far as I could tell. Did some of the voodoo mentioned in the article (removing the plist files), but no permanent fix. It seemed more solid, if I went into the Display settings and allowed for Resolution = 'Default for Display' for the 4K monitor, but not a 100% fix. Probably just anecdotal.

So I tried hooking up both monitors to see what's going on at this point. The 4K monitor may be blank/black (but at least no longer in power save mode), and the 1080 monitor will always work, and can log in from there.

The Mac still tests all good. The network was fine too, turns out it was just falling into sleep mode without someone there to logging in. And the 4K monitor seems all good too, as I've now hooked it up to multiple Windows laptops with no problem.

It seems to point to something software related. I may have to break down and heave-ho all the equipment up to the Apple store at this point, but would like to avoid it if possible. :-(

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Answer 5

amezin

Level 1

4 points

Apr 30, 2017 3:14 PM in response to mk553

I have a problem that, I think, can be related.

Mac Pro 6,1 + Dell P2415Q. "No signal" instead of boot menu and apple logo, then the display starts working when OS boot completes.

Interestingly, the problem goes away if I set "MST" to "Secondary" (in OSD menu). However, with this setting it works at 30 hz only.

I am not sure when exactly it started (I rarely reboot), but most likely its 10.12.4 update.

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Answer 6

mk553 Author

Level 1

9 points

Apr 30, 2017 1:44 PM in response to mk553

Forgot to mention that, at this point, with both monitors hooked up, if I unplug the 4K monitor and re-plug it back in, it always pops back on. For what it's worth.

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