MacBook Pro, late 2011, OX10.12.4, boot problem

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Level 1

19 points

MacBook Pro, late 2011, OX10.12.4, boot problem

I updated to OS X 10.12.4 three weeks ago.

My Mac will not boot. It starts (apple picture, progress bar one, then progress bar disappears) and nothing happens from there. Usually, a second progress bar appears and it finishes booting.

I've tried a number of things suggested on another post. Reset PVRAM and SMC. Both safe and startup manager seem to be bypassed and it still stalled as above.

I was able to do an Apple network startup and run Disk Utilities and hardware test. Neither showed a problem. However, after several ties I could not longer boot from the network and the start up continued to stall as above.

I was able to get it to boot by starting with startup manager and plugging my usb back up drive with Time Machine on it. The disk did not show up as a start up choice. Rather I was asked to connect to my network, after which only my usual internal drive was available for selection, The external drive was not a choice. I chose it and the computer did fully start and is now working fine. I can unplug the external drive and it still works fine. However, when I restart it stalled as above. Starting again with the backup drive connected it booted.

Any ideas?

I am eventually going have to restart without the backup drive available.

MacBook Pro (15-inch Late 2011), Mac OS X (10.4.1), null

Posted on Apr 15, 2017 3:05 PM

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Answer 1

dot.com

Level 4

2,449 points

Apr 15, 2017 3:17 PM in response to Lance Raynor

Kind of sounds like your startup disk is having problems. Which drive did you run the Disk Utility on? If not the normal boot disk, then make sure you tell it that you want to verify or repair the boot disk (usually disk0). If you can get to a terminal window try this:

diskutil list

and let us know the results.

Good luck...

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Answer 2

Lance Raynor Author

Level 1

19 points

Apr 17, 2017 1:52 PM in response to dot.com

I have to amend my post. My MacBook will not complete the startup process. I will see the apple logo, then a progress bar, then a gray screen and it goes no further.

Before this problem the sequence above was followed by a second progress bar and the mac finished its startup.

Now if I attach an external drive that has no system folder on it to a usb port, and start up using the option key (i.e. startup manager) I will be asked to join my network, then I select the drive on my Mac Pro (the only option), it starts and I can use it no problem.

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