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Startup Options Every Mac User Should KnowMarch 3, 2017
Apple company is always concerned about beautiful design and user experience. That’s why most tech details are hidden behind a nice look. However, for some reasons, you may need to look behind the scenes. Here are several startup options that can help you understand the inner organization of your Mac and troubleshoot some issues.
How does it work? This is the most known and probably the most used startup option. Similar to Windows, MacOS has a safe mode. Your computer loads only essential kernel extensions, i.e. hardware and software drivers. Startup apps and services and custom fonts that you installed manually are not loaded. The safe mode cleans system and fonts caches, verifies the integrity of your disk, and tries to repair some errors and issues with directories.
When to use? If your Mac doesn’t start up, it can be caused by both software or hardware problems. To define what’s exactly the reason, boot in the safe mode. If the issue disappeared in the safe mode, boot in the normal mode. If the issue persists, most likely it’s incompatible startup items. If the problem has gone, then it was probably related to the directory caches, and the safe mode fixed it. Thus, the safe mode helps fix or isolate any software issues.
Sometimes the safe mode is used to remove apps that cannot be removed in the normal mode because of a process that you cannot quit. Do not use the safe mode for usual work, as your Mac will be slow, and some apps just won’t work in the safe mode.
How to proceed? To boot in the safe mode, press and hold the Shift key while your Mac is starting up. When you hear the chime, release Shift. You will see a gray screen with the Apple logo on it and a progress bar. To quit the safe mode, restart as usual.
How does it work? Starting from 2011, there’s a recovery partition in MacOS, which takes 650 MB of disk space and allows you to restore system software without using DVDs or USB drives. This partition also has a web browser so you can connect to the Internet and get help online from Apple support. When the recovery mode boots, you will have the following options:
restore from Time Machine Backup;
reinstall OS X;
get Help Online (use Safari to browse Apple support website);
in MacOS Utilities you can also access the Firmware Password Utility, Network Utility, and Terminal.
When to use? It can help you reinstall MacOS, restore your computer from Time Machine backup, as well as repair, erase, and partition your Mac’s internal disks. You can also reset passwords for admin user accounts by using the recovery mode.
How to proceed?
To enter the recovery mode, press and hold the Command-R keys when you hear the startup chime of your Mac. Keep holding down both keys until you see a window with Mac OS Utilities on your screen.
How does it work? Startup Manager is a tool that allows you to boot your Mac from a chosen source, such as your Macintosh HD, Windows via BootCamp, USB drive, external disk, or even network drive. It is similar to BIOS boot menu in Windows.
When to use? If you use Windows on your BootCamp partition, you want to boot to a cloned backup of your system drive, or you want to reinstall MacOS from a DVD or USB drive.
How to proceed? Reboot your Mac, and then press and hold the Option (Alt) key when you hear the startup tone. After that, you will see a gray screen with available options to boot from. The list will automatically update if you plug in an external device. You can also hold down additional keys to boot from a specific source:
pressing C during the startup will boot directly from an inserted CD/DVD or USB bootable drive.
pressing N while booting will start Mac not from the local operating system that is installed on your HD, but from a network-based operating system.
How does it work? If you ever used a Windows computer, you should have noticed a black screen with white letters when booting. This is a startup screen describing what is going on and what is loading now. However, Apple decided to hide this process behind the gray startup screen with the Apple logo and a progress bar. It may look nice and probably more esthetic than running rows of messy symbols, but sometimes these details can be helpful.
When you start up in the verbose mode, your Mac shows you all details of the boot process and then loads your usual OS.
When to use? You can use the verbose mode if your Mac has issues on booting or cannot start up. Probably, those details are not always comprehensive, but at least you will have a hint or information for further research.
How to proceed? To boot in the verbose mode, press and hold the Command-V keys when you hear the startup tone. After that, you will see the rows of text moving, and you will be able to identify the problem.
Single User Mode
How does it work? The single user mode works similarly to the verbose mode. It also shows you details of the startup process, but instead of booting up the OS, this mode will bring you to the text terminal where you can type a command. It’s called ‘single user’ because it doesn’t load the operating system with your user directories. Instead, it brings the superior user called ‘root’, which has all privileges unlike other user accounts, even the administrator.
When to use? You can use the single user mode to fix various issues including hard drive repair. If your Mac does not start up, you can use this mode for advanced diagnostics or troubleshooting. Note that this way of troubleshooting will require some knowledge of UNIX terminal commands. The most used command is fsck that can check and repair the volume’s file system. You can use it by yourself.
How to proceed? To start up in the single user mode, press and hold the Command-S keys. Keep holding the keys until you see lines of white text finishing with root# word on your screen. If you want to check and repair your file system, enter fsck -fy. If you see a message ‘File system was modified’, run fsck again until you see ‘The volume (volume_name) appears to be OK’. After that, you can leave the single user mode by entering either the reboot or exit command. All the way through you will see hints in case you use the wrong syntax or misprint a command. However, be very attentive with the Terminal, as it has no ‘undo’ option.
Target Disk Mode
How does it work? Mac computers have a unique feature that allows you to turn your computer into a hard drive. It is the target disk mode (TDM). You can connect two Macs with FireWire or Thunderbolt and see the contents of Mac’s hard drive in the TDM on another Mac, like you physically pulled out the hard drive from one computer and connected it to another.
When to use? It is easy to transfer files directly from one Mac to another by using the TDM. You can also start one Mac’s operating system on another Mac. In this case, you will use a Mac in the TDM as a bootable drive for another Mac.
How to proceed? To set up the target disk mode, connect two computers with FireWire, Thunderbolt, or USB-C cable supporting sufficient data transfer speed. Hold down the T key to start a computer that you want to become a disk. When it turns on, you will see the icon of a disk on another computer. Now you can copy the files like you would do with any other removable drive.
If you want to run one Mac’s OS on another Mac, put your target computer into the target disk mode and connect it to another Mac. After that, call Startup Manager on the host computer and choose your target disk Mac as a boot source.
Knowing these startup options will help you learn more about your Mac processes and be more experienced in resolving different issues. Sometimes such knowledge may even save you money that you would need to spend on a visit to a specialist.