How to Troubleshoot Startup Problems With Your Mac

10 tips for getting your Mac working again

What to Know

  • Create a spare user account and use Safe Boot to troubleshoot startup errors.
  • Use keyboard shortcuts to control the startup process.
  • Reset the PRAM or NVRAM and reset the SMC. Use macOS combo updates if necessary.

This article explains how to troubleshoot startup problems with your Mac. The instructions apply to all macOS computers and laptops.

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Mac User account creating a spare account

A spare user account with administrative capabilities can help you troubleshoot problems with your Mac.

The purpose of a spare account is to have a pristine set of user files, extensions, and preferences to load at startup. This can often get your Mac running if your main user account is having problems, either at startup or while you're using your Mac. Once your Mac is up and running, use a variety of methods to diagnose and repair the problem.

You must create the account before trouble strikes, though, so be sure to put this task at the top of your to-do list.

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Try Safe Boot to Fix Startup Problems

Macbook displaying Safe Boot

The Safe Boot option is one of the most often used methods for diagnosing problems. It essentially forces the Mac to start up using the fewest possible system extensions, fonts, and other ​startup items. It also checks your startup drive to ensure that it's in good shape or at least bootable.

When you're having startup problems, Safe Boot can help you get your Mac up and running again.

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Solve Startup Issues by Resetting PRAM or NVRAM

A closeup of two sticks of computer RAM under a soft blue light
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The Mac's PRAM or NVRAM (depending on the age of your Mac) holds some of the basic settings necessary for it to boot successfully, including which startup device to use, how much memory is installed, and how the graphics card is configured.

Solve some startup issues by giving the PRAM/NVRAM a kick in the pants. This guide will show you how.

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Reset the SMC (System Management Controller) to Fix Startup Problems

People holding and looking at MacBook Air at Apple Store

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The SMC controls many of the Mac's basic hardware functions, including managing sleep mode, thermal management, and how the power button is used.

In some cases, a Mac that won't finish starting up, or starts up and then freezes, may need its SMC reset.

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Fix a Flashing Question Mark at Startup

Man using a computer in bed room

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When you see a flashing question mark during startup, your Mac is telling you that it's having trouble finding a bootable operating system. Even if your Mac eventually finishes booting, it's important to address this problem and make sure the correct startup disk is set.

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Fix it When a Mac Stalls on Gray Screen at Startup

Sad looking person looking at iMac

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The Mac's startup process is normally predictable. After you push the Power button, you see a gray screen (or a black screen, depending on the Mac you're using) while your Mac searches for the startup drive, and then a blue screen as your Mac loads the files it needs from the startup drive. If all goes well, you'll end up at the desktop.

If your Mac gets stuck at the gray screen, you have a bit of detective work ahead of you. Unlike the blue screen problem (mentioned below), which is straightforward, there are a number of culprits that can cause your Mac to get stuck at the gray screen.

It may be easier than you think to get your Mac running again, although it may also take a bit of time.

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What to Do when a Mac Stalls at the Blue Screen During Startup

Mac Blue Screen


If you turn on your Mac, make it past the gray screen, but then get stuck at the blue screen, it means your Mac is having trouble loading all the files it needs from the startup drive.

This guide will take you through the process of diagnosing the problem's cause. It may also help you perform the repairs needed to get your Mac up and running again.

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Get Your Mac Running so You Can Repair the Startup Drive

A stethoscope resting on a hard drive

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Many startup problems are caused by a drive that needs minor repairs. But you can't perform any repairs if you can't get your Mac to finish booting.

This guide shows you tricks to get your Mac up and running, so you can repair the drive with Apple or third-party software. We don't limit the solutions to only one method of getting your Mac to boot. We also cover methods that could help you get your Mac running to the point where you could repair the startup drive or further diagnose the problem.

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Use Keyboard Shortcuts to Control the Mac's Startup Process

Photograph of an Apple wireless keyboard

 David Paul Morris / Getty Images

When your Mac won't cooperate during startup, you may need to force it to use an alternate method, such as booting in Safe Mode or starting from a different device. You can even have your Mac tell you each step it's taking during startup, so you can see where the startup process is failing.

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Use OS X Combo Updates to Correct Installation Problems

OS X Yosemite Presentation

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Some Mac startup problems are caused by a macOS or OS X update that went bad. Something happened during the installation process, such as a power hiccup or power outage. The result can be a corrupt system that won't boot or a system that boots but is unstable and crashes.

Trying again with the same upgrade install is unlikely to work because upgrade versions of the OS don't include all the necessary system files, only the ones that are different from the previous version of the OS. Because there's no way of knowing which system files may have been affected by a corrupt install, the best thing to do is to use an update that contains all necessary system files.

Apple provides this in the form of a combo update. This guide will show you how to obtain and install combo updates.

You should always have a current backup of all of your data. If you don't have a current backup, head over to Mac Backup Software, Hardware, and Guides for Your Mac, select a backup method, and then put it into action.

  • How do I stop apps from opening at startup on my Mac?

    To disable startup programs on a Mac, go to the Login Items tab in your System Preferences and click the Lock to unlock the screen for changes. Choose a program, then click the minus sign (-) to remove it.

  • How do I turn off the startup sounds on my Mac?

    To silence the startup chime on a Mac, select Apple icon > System Preferences > Sound Preferences > Output > Internal Speakers. Move the Output volume slider at the bottom of the Sound window to turn it off.

  • How do I free up space on my Mac startup disk?

    To free up space on your Mac's startup disk, use the Managed Storage and Storage Graph features to determine which files you should remove. To clear space, empty the trash, uninstall applications, delete mail attachments, and clear the system cache.

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