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Your Mac doesn’t start up? We may be able to fix that

Have you ever had a Mac that didn’t want to start up? Perhaps it was stuck on that gray startup screen with a spinning wheel, without completing the process so you could log in and start working.

That’s exactly what happened with one of the Macs in the Pingdom office. It was a MacBook Pro 15-inch that just had that gray screen and spinning wheel forever, not moving on to the next part of the boot-up process, whatever that was.

Here’s what we did to fix it. It may help you too, at some point in the future.

Zap the NVRAM

Try this first as it could fix the problem before you move on the other steps. Clearing the NVRAM (NV stands for Non Volatile) will erase some settings on your Mac. It will not erase any files, but it will erase settings for speaker volume, startup disk, monitor depth, and some other settings.

To clear the NVRAM, and the settings it holds, hold down Command + Option + P + R (all four at the same time) when you start up your Mac, and hold them down until you hear the startup sound a second time. Then you can let go.

Apple has a detailed description of this.

Verbose mode

Verbose mode is a fancy way of saying that the Mac will startup with the command line showing, so you can see everything it does. If all goes well, it continues into the graphical frontend of Mac OS X, just as normal.

The benefit is if something is not working, you are likely to see where it goes wrong. Chances are the last thing you see on the screen is where something messes up. That, at least, gives you a better idea of where to start looking when troubleshooting.

To start in verbose mode, just hold down Command + V when you start up your Mac.

If you wish your Mac to always boot in verbose mode, you can set it accordingly by entering the following in Terminal:

sudo nvram boot-args="-v"

To disable it, you enter this in Terminal:

sudo nvram boot-args=

Single-user mode

Single-user mode is like verbose mode, but the Mac does not continue into the graphical part of Mac OS X. Instead, it starts up the command line.

To start in single-user mode, hold down Command + S when starting up your Mac. Like with verbose mode, you will see commands scroll by on the screen. When it stops, you can run the command for checking the startup disk to see if it’s feeling okay. You do that by typing in the following, and enter.

/sbin/fsck -fy

Then when it has run through fsck and hopefully reported that all is well, you reboot the Mac by entering this, followed by enter:

reboot

Your Mac should then reboot and hopefully it starts up without issues. If so, you’ve just fixed the Mac but you should take a backup just as fast as you can, just in case.

Hopefully you can now troubleshoot your Mac

So there you go, some simple troubleshooting for your Mac in case it refuses to start up. The MacBook Pro that we had problems with is fine and up and running like normal again. For us, these steps helped fix the issue. We hope it can do the same for you.

Sick Mac image via Shutterstock.



43 comments
oliverwa
oliverwa

Clearing NVRAM doesn't always work. What else can I do to fix a non-booting Macbook pro. 2007 vintage.

oliverwa
oliverwa

Does not work everytime. What else can I do?

sazz2006
sazz2006

Zap the NVRAM  works for me. Thank u

son101
son101

tank you for the effort 

so is it like doing all three steps one by one or they are three methods to fix the issue? 

as i did the first step it froze again then i had to press long start  and get to cmd+v   but again it stopped at the<< yukon: ethernet address >>  

any tips ?

ReZamp
ReZamp

I have unique information received from this site. This is the ideal blog and full of information. We should share more techniques.
https://twitter.com/re_zamp 

HELP PLEASE_MAC
HELP PLEASE_MAC

When I hold down command+option+P+R nothing happened

And how are you going to run terminal if it's not booting up?

When I put in the fsck thingy it said the volume Macintosh HD could not be repaired.

?"???????

pchealerltd
pchealerltd

How are you going to run terminal if its not booting up? 


pchealerltd
pchealerltd

How are you going to run terminal if its not booting up?

planning
planning

Thank you for sharing your stuff on blog. It is doubtless that we have similar interests. Something are very helpful to me.

planning
planning

Thank you for sharing your stuff on blog. It is doubtless that we have similar interests. Something are very helpful to me.

iMac no power repair
iMac no power repair

Before two days i got my new mac, the problem which is arising is that, It restarts automatically, and again turn of i checked as well as other hardware but believe me, It was doing the same, Now tell me something what is to do??

entrepreneurs
entrepreneurs

It is very nice to see this site and it's really informative for the readers. It is really nice to see the best information presented in an easy and understanding manner. Thank you.

Connecticut
Connecticut

After an instruction is fetched, the PC is incremented by the length of the instruction word in terms of memory units. Often, the instruction to be fetched must be retrieved from relatively slow memory, causing the CPU to stall while waiting for the instruction to be returned. This issue is largely addressed in modern processors by caches and pipeline architectures.

Magzworld
Magzworld

Thank you! I haven't been able to diagnose my mac for months until this. Failed RAM but this was where I needed to start. Thank you thank you. 

Magzworld
Magzworld

Thank you! I haven't been able to diagnose my mac for months until this. Failed RAM but this was where I needed to start. Thank you thank you. 

stromarchitects
stromarchitects

@Daveybot thanks had tried PRam, but the computer dosent boot at all.... Tried different screen but no out signal...

stromarchitects
stromarchitects

@Daveybot thanks had tried PRam, but the computer dosent boot at all.... Tried different screen but no out signal...

Terjeminator
Terjeminator

@pingdom #Macs should never need to have problems!!!!!!!!!!!!!!!!

Terjeminator
Terjeminator

@pingdom #Macs should never need to have problems!!!!!!!!!!!!!!!!

Todd Motto
Todd Motto

I've seen it get stuck after an update about a year ago, and also after shutting down once. Holding the button for OFF fixed it.

Todd Motto
Todd Motto

I've seen it get stuck after an update about a year ago, and also after shutting down once. Holding the button for OFF fixed it.

dinil
dinil

thank you so much information

dinil
dinil

thank you so much information

pingdom
pingdom

@Livefyre Thanks very much - we're excited about the new possibilities for our blogs :)

pingdom
pingdom

@Livefyre Thanks very much - we're excited about the new possibilities for our blogs :)

Keith Gable
Keith Gable

Mine never does either, but sometimes my Mac will do a fsck on boot (all Unixes do), detect some error, and then go about fixing it. Except that you don't see this if you are not in verbose mode - you see the Apple logo while it fscks. When this happens to me, it seems to take hours. So now I boot with verbose mode on always, so if it's fscking (instead of frozen), I know to let it sit there... (Then again, I have gigabytes of tiny files, so I'm probably an edge case.)

Keith Gable
Keith Gable

Mine never does either, but sometimes my Mac will do a fsck on boot (all Unixes do), detect some error, and then go about fixing it. Except that you don't see this if you are not in verbose mode - you see the Apple logo while it fscks. When this happens to me, it seems to take hours. So now I boot with verbose mode on always, so if it's fscking (instead of frozen), I know to let it sit there... (Then again, I have gigabytes of tiny files, so I'm probably an edge case.)

Pingdom
Pingdom

In our case, the fsck actually didn't report any error, but the Mac has worked fine since we ran it.

Pingdom
Pingdom

In our case, the fsck actually didn't report any error, but the Mac has worked fine since we ran it.

Keith Gable
Keith Gable

Also it's worth mentioning that sometimes, a boot-time fsck takes hours. It may not be dead, and could just be fscking away.

Keith Gable
Keith Gable

Also it's worth mentioning that sometimes, a boot-time fsck takes hours. It may not be dead, and could just be fscking away.

Barbara Wenke
Barbara Wenke

What a Mac not booting up correctly unheard of

Barbara Wenke
Barbara Wenke

What a Mac not booting up correctly unheard of

Abcslayer Là Tôi
Abcslayer Là Tôi

it would be a MBP of "SantaRosa" or "Penryn" platform (2008-2009), the NVIDIA GPU is faulty. Apple will repair this one for free (not really sure the program still effective till this 2012)

Abcslayer Là Tôi
Abcslayer Là Tôi

it would be a MBP of "SantaRosa" or "Penryn" platform (2008-2009), the NVIDIA GPU is faulty. Apple will repair this one for free (not really sure the program still effective till this 2012)

German Hoeffner
German Hoeffner

No, but my Macbook Pro which is 3 years old doesn't boot at all anymore. Repair costs 1500€. Apple = scam.

German Hoeffner
German Hoeffner

No, but my Macbook Pro which is 3 years old doesn't boot at all anymore. Repair costs 1500€. Apple = scam.

MarkusTenghamn
MarkusTenghamn

Using the option key during startup to select the correct drive or maybe your OSX disc is a simple test which may work especially if you have multiple partitions as I do.

 

Unfortunately in my case when this happened last time it was on a hard drive that crashed, luckily I had done a time machine backup 3 days back and simply replaced the hard drive :)

MarkusTenghamn
MarkusTenghamn

Using the option key during startup to select the correct drive or maybe your OSX disc is a simple test which may work especially if you have multiple partitions as I do.   Unfortunately in my case when this happened last time it was on a hard drive that crashed, luckily I had done a time machine backup 3 days back and simply replaced the hard drive :)

Daveybot
Daveybot

@stromarchitects Aw, I'm sorry. My MacBook died about 3 months ago - it's horrible. Good luck to you!

Daveybot
Daveybot

@stromarchitects Aw, I'm sorry. My MacBook died about 3 months ago - it's horrible. Good luck to you!