To use any of these key combinations, press and hold the keys immediately after pressing the power button to turn on your Mac, or after your Mac begins to restart. Keep holding until the described behavior occurs.
- Command (⌘)-R: Start up from the built-in macOS Recovery system. Or use Option-Command-R or Shift-Option-Command-R to start up from macOS Recovery over the Internet. macOS Recovery installs different versions of macOS, depending on the key combination you use while starting up. If your Mac is using a firmware password, you're prompted to enter the password.
- Option (⌥) or Alt: Start up to Startup Manager, which allows you to choose other available startup disks or volumes. If your Mac is using a firmware password, you're prompted to enter the password.
- Option-Command-P-R:Reset NVRAM or PRAM. If your Mac is using a firmware password, it ignores this key combination or starts up from macOS Recovery.
- Shift (⇧): Start up in safe mode. Disabled when using a firmware password.
- D: Start up to the Apple Diagnostics utility. Or use Option-Dto start up to this utility over the Internet. Disabled when using a firmware password.
- N: Start up from a NetBoot server, if your Mac supports network startup volumes. To use the default boot image on the server, hold down Option-N instead. Disabled when using a firmware password.
- Command-S: Start up in single-user mode. Disabled in macOS Mojave or later, or when using a firmware password.
- T: Start up in target disk mode. Disabled when using a firmware password.
- Command-V: Start up in verbose mode. Disabled when using a firmware password.
- Eject (⏏) or F12 or mouse button or trackpad button: Eject removable media, such as an optical disc. Disabled when using a firmware password.
If a key combination doesn't work
If a key combination doesn't work at startup, one of these these solutions might help:
If you want to dual boot the USB, select another kind of disk, if not select an 8GB thumb drive. Select Chose an 8 GB USB. Choose the disk which you want to boot their MacOS High Sierra 10.13. Choose the Disk to Erase. Once you select the disk it will erase the disk, in other words, it will partition the disk as macOS needs. Download the Windows 10 ISO disk image from Microsoft using this link. Choose the 64-bit version.
- Be sure to press and hold all keys in the combination together, not one at a time.
- Shut down your Mac. Then press the power button to turn on your Mac. Then press and hold the keys as your Mac starts up.
- Wait a few seconds before pressing the keys, to give your Mac more time to recognize the keyboard as it starts up. Some keyboards have a light that flashes briefly at startup, indicating that the keyboard is recognized and ready for use.
- If you're using a wireless keyboard, plug it into your Mac, if possible. Or use your built-in keyboard or a wired keyboard. If you're using a keyboard made for a PC, such as a keyboard with a Windows logo, try a keyboard made for Mac.
- If you're using Boot Camp to start up from Microsoft Windows, set Startup Disk preferences to start up from macOS instead. Then shut down or restart and try again.
Remember that some key combinations are disabled when your Mac is using a firmware password.
Learn more
- Learn what to do if your Mac doesn't turn on.
- Learn about Mac keyboard shortcuts that you can use after your Mac has started up.
Here are some solutions for accessing the files on your Macintosh Hard Drive when your drive will not boot to the desktop.
Mac Boot Disk Usb
A Mac can be started via a USB port, with a USB key or external hard drive, but that device needs to have Mac OSX system installed on it to boot, as well as other requirements. Best bet is to always backup your Mac hard drive with a bootable image created by Apple Disk Utility or a third party utility such as Carbon Copy Cloner. The easiest way to keep your files backed-up is by using Time Machine, which is built in to the Apple OS. The only requirement for Time Machine is to have an attached hard drive to back your files up to.
Boot Disk For Mac Pro
If you don't have a bootable backup, or a way to get a Mac drive, you will need to boot the computer from another operating system.
First, try to boot your Mac in Recovery mode, holding down Cmd-r on restart. If that doesn't work, try for Internet Recovery, which is restart and hold down Cmd-Opt-R.
Apple OSX Internet Recovery Article: https://support.apple.com/en-gb/HT201314
Secondly, you can try to boot your Mac into Safe mode to see if you can boot to a minimal desktop.
Start or restart your Mac. Immediately after you hear the startup sound, press and hold the Shift key. Tuned in for macbook.
Release the Shift key when you see the Apple logo appear on the screen.
Realvnc enterprise for mac. After the Apple logo appears, it might take longer than usual to reach the login screen or your desktop. This is because your Mac performs a directory check of your startup disk as part of safe mode.
To leave safe mode, restart your computer without pressing any keys during startup.
Apple Article on booting your Mac into Safe Mode: https://support.apple.com/en-us/HT201262
If neither of those work, find another Mac, connect it to your Mac with Firewire or Thunderbolt cable. Then reboot the non-bootable Mac holding down the 't' key, which puts it in Target Disk Mode. If this works, the Mac hard drive will appear as a mounted drive on the other Mac.
Apple Article on installing OSX on an External Hard Drive so you can boot from it: https://support.apple.com/en-gb/HT202796
Apple Article for creating a bootable installer for OSX Yosemite (10.10) & OSX El Capitan (10.11): https://support.apple.com/en-gb/HT201372
Apple Article: Booting Into Target Disk Mode For File Transfer: https://support.apple.com/kb/PH10725?locale=en_US
Once you have booted from an external drive, and you can mount the you hard drive that was not booting, you can search the drive for files to recover, beginning with the files that are in the /Users/Home/ Directory.
Accessing Hard Drives That Have Been Encrypted Using File Vault
If you want to dual boot the USB, select another kind of disk, if not select an 8GB thumb drive. Select Chose an 8 GB USB. Choose the disk which you want to boot their MacOS High Sierra 10.13. Choose the Disk to Erase. Once you select the disk it will erase the disk, in other words, it will partition the disk as macOS needs. Download the Windows 10 ISO disk image from Microsoft using this link. Choose the 64-bit version.
- Be sure to press and hold all keys in the combination together, not one at a time.
- Shut down your Mac. Then press the power button to turn on your Mac. Then press and hold the keys as your Mac starts up.
- Wait a few seconds before pressing the keys, to give your Mac more time to recognize the keyboard as it starts up. Some keyboards have a light that flashes briefly at startup, indicating that the keyboard is recognized and ready for use.
- If you're using a wireless keyboard, plug it into your Mac, if possible. Or use your built-in keyboard or a wired keyboard. If you're using a keyboard made for a PC, such as a keyboard with a Windows logo, try a keyboard made for Mac.
- If you're using Boot Camp to start up from Microsoft Windows, set Startup Disk preferences to start up from macOS instead. Then shut down or restart and try again.
Remember that some key combinations are disabled when your Mac is using a firmware password.
Learn more
- Learn what to do if your Mac doesn't turn on.
- Learn about Mac keyboard shortcuts that you can use after your Mac has started up.
Here are some solutions for accessing the files on your Macintosh Hard Drive when your drive will not boot to the desktop.
Mac Boot Disk Usb
A Mac can be started via a USB port, with a USB key or external hard drive, but that device needs to have Mac OSX system installed on it to boot, as well as other requirements. Best bet is to always backup your Mac hard drive with a bootable image created by Apple Disk Utility or a third party utility such as Carbon Copy Cloner. The easiest way to keep your files backed-up is by using Time Machine, which is built in to the Apple OS. The only requirement for Time Machine is to have an attached hard drive to back your files up to.
Boot Disk For Mac Pro
If you don't have a bootable backup, or a way to get a Mac drive, you will need to boot the computer from another operating system.
First, try to boot your Mac in Recovery mode, holding down Cmd-r on restart. If that doesn't work, try for Internet Recovery, which is restart and hold down Cmd-Opt-R.
Apple OSX Internet Recovery Article: https://support.apple.com/en-gb/HT201314
Secondly, you can try to boot your Mac into Safe mode to see if you can boot to a minimal desktop.
Start or restart your Mac. Immediately after you hear the startup sound, press and hold the Shift key. Tuned in for macbook.
Release the Shift key when you see the Apple logo appear on the screen.
Realvnc enterprise for mac. After the Apple logo appears, it might take longer than usual to reach the login screen or your desktop. This is because your Mac performs a directory check of your startup disk as part of safe mode.
To leave safe mode, restart your computer without pressing any keys during startup.
Apple Article on booting your Mac into Safe Mode: https://support.apple.com/en-us/HT201262
If neither of those work, find another Mac, connect it to your Mac with Firewire or Thunderbolt cable. Then reboot the non-bootable Mac holding down the 't' key, which puts it in Target Disk Mode. If this works, the Mac hard drive will appear as a mounted drive on the other Mac.
Apple Article on installing OSX on an External Hard Drive so you can boot from it: https://support.apple.com/en-gb/HT202796
Apple Article for creating a bootable installer for OSX Yosemite (10.10) & OSX El Capitan (10.11): https://support.apple.com/en-gb/HT201372
Apple Article: Booting Into Target Disk Mode For File Transfer: https://support.apple.com/kb/PH10725?locale=en_US
Once you have booted from an external drive, and you can mount the you hard drive that was not booting, you can search the drive for files to recover, beginning with the files that are in the /Users/Home/ Directory.
Accessing Hard Drives That Have Been Encrypted Using File Vault
If the hard drive you are trying to recover data from has been encrypted with File Vault, and you don't know the login password, you will need to use a Recovery Key to login into the drive so you can access the data.
Retrieved 2009-05-16. Coreldraw graphics suite x4 for mac. Retrieved 2018-08-20. Retrieved 2016-04-26. Arah, Tom (January 2008).
You can access the Recovery Key from the Caper JAMF Software Server on campus. Log into the JSS: https://Casperserver.iowa.uiowa.edu:8443.
Boot Disk For Mac 10.6.8
For the step by step process to retrieve a Recovery Key, see ITS Support article:http://its.uiowa.edu/support/article/104815