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.
We've gathered 10 of the best tips for getting your Mac working again. Some of the tips address specific types of problems; some are more general in nature. And some tips, such as creating a spare user account, 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.
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 normal 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.
The Mac's startup process is normally predictable. After you push the power button, you see a gray screen 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.
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.
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.
The Mac's PRAM 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 a kick in the pants. This guide will show you how.
If your Mac displays a question mark when you power it on it's having a problem figuring out which of the available devices is the startup device. 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.
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.
This guide lists all of the Mac's startup-related keyboard shortcuts.
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.