If your Mac seems to be giving you trouble, the troubleshooting process isn’t all that different from what it is on a Windows computer. You have access to a number of special modes that help you get under your Mac’s hood. Try these methods.
If you need help from Apple Support or need to restore your malfunctioning computer to working order, Recovery Mode can help you. You boot into this mode by pressing down Command + R after pressing the power button. Once in Recovery Mode , the Mac will ask to be connected to the network or the Internet to be able to access recovery software online.
Recovery Mode gives you access to 4 OS X utilities: Time Machine backup to restore your computer to an earlier state, OS X reinstallation to format your computer and start afresh, a disk utility to erase or repair a storage device and access to Apple Support.
The recovery process is user friendly. You don’t need to learn any specific installation techniques — you simply need to tell your Mac what you want it to do. It downloads whatever it needs and gets your computer to the state you ask for, all by itself.
The Startup Manager
If you need your Mac to boot up to something other than the default storage device, you need to hold down the Option key as soon as you press the power button. Right away, you’ll see the Startup Manager with its icons for different hard disks, DVD drives, network locations and thumb drives for you to boot from.
If you would like your Mac to directly boot to a specific non-default device without having to look at the list on the Startup Manager, OS X has a different default key for each type of device. If you wish to boot off the network, for instance, you hold down the N key. If it’s the CD or DVD, you hold down C .
Booting into Safe Boot
What Windows calls Safe Mode, OS X calls Safe Boot– the computer only loads enough software to get the system up and running. Third-party drivers, software and fonts don’t load. If your Mac is giving you trouble, booting into Safe Mode will help you isolate the cause of the problem.
Booting into Safe Boot mode is easy — you only need to hold down the Shift key right after you press the power button.
Single-user mode and Verbose mode
Single-user mode can be useful troubleshooting problems. In this mode, the Mac starts up to a root shell and runs in text-based terminal mode. You can enter this mode but pressing down Command + S after the power key.
Holding down Command + V after the power button boots your computer into Verbose mode. You’ll see detailed text-based terminal messages as the computer starts up. If there is a malfunctioning component, you’ll be able to learn something about it from the messages you see. If all is well with your computer, it should boot regularly once it runs through all the messages associated with the startup process.