Troubleshooting Tips for Mac Startup Problems

Your Mac is probably generally trouble-free, working day after day without complaint. Many of us are lucky enough to go for years without running into any problems that keep our Macs from starting up. But when and if your Mac refuses to finish booting, it can be a disaster, especially if it happens when you're working against a deadline.

These 10 tips for getting your Mac working again address specific types of problems; some are more general in nature. And some tips, are designed to help you prepare for problems in advance, rather than actually diagnose them.

Speaking of being prepared, 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 to Use Your Mac's Safe Boot Option

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 running again.

How to Reset Your Mac's PRAM or NVRAM (Parameter RAM)

Old computer


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.

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

Resetting the SMC (System Management Controller) on Your Mac

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The SMC controls many of 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 just need its SMC reset.

My Mac Displays a Question Mark When It Boots. What Is It Trying to Tell Me?

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Even if your Mac eventually finishes booting, it's a waste of your time to let the Mac try to solve the problem on its own. This guide will show you how to set your Mac's startup device.

Mac Stalls on Gray Screen at Startup

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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 are 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 pretty straightforward, there are a number of culprits that can cause your Mac to get stuck at the gray screen.

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

Troubleshooting Mac Startup Problems - Stuck at the Blue Screen

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 cause of the problem. It may also help you perform the repairs needed to get your Mac up and running again.

How Can I Repair My Hard Drive If My Mac Won't Start?

A stethoscope resting on a hard drive

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Many startup problems are caused by a drive that just needs some 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 try to repair the drive with Apple or third-party software. We don't limit the solutions to just one method of getting your Mac to boot but cover any methods that could help and let you get your Mac running to the point where you could repair the startup drive or further diagnose the problem.

Mac OS X Startup Keyboard Shortcuts

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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.

Use OS X Combo Updates to Correct Installation Problems

OS X Yosemite Presentation

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Some Mac startup problems are caused by an OS X update that went bad. Something happened during the installation process, such as a power hiccup or power outage. The end 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 necessary system files, just 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 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.

Create a Spare User Account to Assist in Troubleshooting

Troubleshooting tips for Mac startup problems

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 that can be loaded at startup. This can often get your Mac running if your depending user account is having problems, either at startup or while you're using your Mac. Once your Mac is up and running, you can 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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