i have a brand new MacBook pro and it won't boot up. The bar gets to 1/4 of an inch from complete and then starts over. Its in an endless loop of this. How do I get out?

Held down shift key for an entire cycle, but made no difference. New MacBook Pro is still cycling endlessly. Goes black, Apple logo appears, bar starts to fill quickly under it, hits halfway point and slows down, hangs up about a quarter inch from the end, sits there a while, then starts over again.

Having this same problem

Held down shift key for an entire cycle, but made no difference. New MacBook Pro is still cycling endlessly. Goes black, Apple logo appears, bar starts to fill quickly under it, hits halfway point and slows down, hangs up about a quarter inch from the end, sits there a while, then starts over again.

If as you say "Brand New MacBook Pro", is there a reason you are posting in High Sierra? HS is three years old OS. A Brand New MacBook Pro would not, under normal circumstance come with a 3 year old OS. Should be at least Mojave if not Catalina.

I'm having this same problem on a Macbook Pro early 2011 running High Sierra.

I have reinstalled the OS a couple of times. Utility says drive is OK. Done all the things to solve this several times.

I'm a computer specialists with more than 35 years using, repairing, and selling Macs.

I'm a Retired Air Force computer programmer/analyst.

Maybe my 73 years is saping my brain. Ha. Ha.

I have the same problem since I updated to the newest version of Mac OS X. My MBP has a broken left shift key since it went for repair in Bangkok. Both USB and HDMI ports are switched out by software. There is a method to reset the controllers using Terminal but it is rather complicated. I'm also a retired computer aged 81. Can ANYONE help with this problem? Please!

Safe Boot from the HD, (holding Shift key down at startup), does the problem occur in Safe Mode?

Any luck with that?

Did you ever solve this? Did you send it back for a replacement? Maybe they sent me your machine. Bad joke.

Time to return it.

I just got a MacBook Pro yesterday and I’m having the EXACT SAME ISSUE.

Don’t know if it is High Sierra

Still the same issue?

This is very probably a corrupted cache in the firmware.

Bring it back !