MacPro 2013 Yosemite -- won't start up, monitor never turns on, repeatedly reboots itself

Thank you nurrrrik... You just save my life. I have searched a lot in web but didn't find any solution. After your instruction I get back my mac mini is started working.

But unfortunately it shows blank screen after reboot by manually. Then I just do one additional task.

After hearing second chime I just released OPTION+P key. So it sound chime 3rd time started in internet recovery mood. Hope that will make my mac mini working fine.

Thank you again. 🙂

Darn! It worked for a few days. Tried to start my Macbook Pro this morning and can't even get a chime. Any suggestions?

I have a MacPro (Late2013) model which *was* the best Apple computer I've ever used in my 20+ years of using Apple computers.

That all changed when I upgraded to Yosemite. I have a main monitor (Apple LED 27") connected to the computer and a secondary monitor (ViewSonic 24"). Each use the AMD FirePro D500 3072 MB graphics card.

After upgrading to Yosemite, the secondary monitor would briefly flash on startup but then go into "power saving mode" meaning it wasn't receiving a signal.

I tried unplugging the secondary monitor's USB+Firebolt cables and trying different port combinations on the back of the MacPro, but nothing worked.

I tried resetting the PRAM and the first time it actually worked. However, the next morning I booted up the machine and the same "no signal" bug came back.

So... Here's my convoluted workarounds:

#1. If I do shutdown the computer at the end of the day, BEFORE I boot up the next morning I manually unplug the Apple LED main computer first, then start up the computer with only the secondary monitor attached. This "forces" the MacPro to "see" the secondary monitor and once I see the login window on the secondary monitor, I then plug in the main Apple monitor and viola!, both monitors work as they did before the Yosemite upgrade.

#2. Once I do have both monitors working as they should, I don't shut down the computer at the end of the day, but just "log out"... the monitors eventually go to sleep, but both respond when awakened the next day.

PLEASE let me know if there is a better way to fix this than this torturous method!!

This was just the tip I needed. Try looking with a flashlight first, before doing the hard restart. If you see the logo by use of a flashlight, then you don't need to hard restart.

I just used the flashlight on my iPhone, held at an angle towards the center of the screen instead of straight on. Once I verified I could see the user & guest avatars / logos, shined the light on the corner of the screen and moved my mouse accordingly in the same direction until I could find my mouse. After finding my mouse on the darkened screen, I moved it (following it with my flashlight) until I could click in my password field under by user avatar, typed in my password, hit return, and my MPB logged in as normal with a fully bright screen after logging had completed.

I have a Mac Pro (2014) with 2 Apple 30" cinema displays and since upgrading to Yosemites I have had the same problem, only 1 monitor starts up each morning. However I've found if I unplug the other monitor from the MacPro and plug it straight back in it comes on straight away. How comes Apple seem to take so long so sort bugs out these days. This thread started in October and its now December with seemingly no update from Apple to sort it out.

I had been using a MPD to HDMI with audio converter. I saw a "video error detected" then i had to power down the MBP manually.

-Reset manually with power button... did not help, just reset to gray screen.

-Reset with option, was able to get to password, but then it went to gray.

-Reset to PRAM and worked fine again.

OK Sportsfans

Just had a customer who had this issue, turned on the MBP 10.10.1 Yosemite with the black screen after startup chime and then into reset your password screen minutes later.

The flashlight on the screen in a dark room reveled the login page as others have stated, once I entered the new password I created on other attempts to fix the issue I was directed to the Keychain page where I entered the orignal password in the update Keychain password supplied by the customer and viola, straight back in and restarting as per normal.

I believe this to be a software issue that does not light up the backlight on occasion, sorry I can't tell you more on the actual sysptoms that caused the problem, but i'm pretty sure it was when coming out of sleep mode.

Kudos to the other posters figuring out the backlight issue.

Thank you! Tears are rolling down my face, as I desperately tried to struggle with a macbook pro bought from ebay, which had these problems,

and your solution worked. I am sure you would rather get money sent to you via paypal acct,. I would offer a booty call but I am over 64 years old.

Hi guys,

i think it's not an hardware issue. I had the same problem on a mid2009 MBP with Yosemite 10.10.2, everything was working fine but a morning, turning the system on, after the chime the display seemed to remain off, no backlit but the system was on. After two or three reboots pressing the power button a window asking if i forgot the password popped up, followed the instructions to enter my pass (obviously i had not forgot it) and the system booted ok. This gave me a hint and after some searching i found that the problem was with FileVault, Apple's encryption system for osx, i had to disable it and never had this issue again.

Luca

I can confirm FileVault is the culprit here. I have never had this problem until turning on FileVault with the Yosemite upgrade. I've got the latest MacMini and the Thunderbolt display, no secondary display. At some point when the system goes into sleep mode the display never comes back on, just a black screen. I push the power button on the macmini and I hear a chime but again no display. I have to unplug the power (and for good measure the thunderbolt cable) and plug it back in. This action will always boot up the computer with the display on. I then have to reset (or recover) the password which leads to another restart. This fixes the problem until the next time. I removed the FileVault and have never experienced the problem again.

Worked for me. I can't believe I had to use a flashlight. Thank you!

Flashlight didnt work for me - until I went into a dark room and then held my iphone flashlight at the top/behind the macbook pro.

Then I could see the login options and the cursor.

Entered password and hey presto - in.

Amazing yet ridiculous at the same time that we have to do this, but very relieved now.

Same thing here but as Illass said, when I disconnected one monitor (got a trashcan with a flass ssd) it booted up okay. But what did you do to fix it once it's up?

Had the same issue. Filevault on my MBPro 15", mid-2009, with current OS X El Capitan, appeared to be the issue. Disabling Filevault solved it.