
Use macOS Recovery
macOS Recovery provides tools to reinstall macOS, use Disk Utility, or access the Terminal. You could guide a user to use macOS Recovery to perform system maintenance, troubleshooting, and security configuration.
macOS Recovery system startup options
macOS Recovery provides several system startup options to help troubleshoot and manage a system. You can access these options with these steps:
- Turn off Mac. 
- Press and hold the power button until “Loading startup options” appears. 
- Click Options, then click Continue to enter macOS Recovery. - Option - Function - Description - Disk Utility - Lets you repair or erase the internal storage and connected devices. - Use First Aid to check and repair file system errors, and also erase and reformat storage. - Install or Reinstall macOS - Installs the current version of macOS that the Mac was previously using. - If you installed a macOS upgrade and then used Disk Utility to erase the disk, you might get the macOS that you were using before upgrading. - Recovery Assistant - Recovery identifies and attempts to resolve any issues it discovers. - This Mac encountered an issue while starting. The recovery process looks for any problems and attempts to resolve them if found. If you still need help, see support.apple.com/mac/recovery. - Web Browser - Browse Apple’s support site or other resources - This option is a limited browser that’s useful for troubleshooting or looking up Apple Support articles during recovery. - Share Disk - Share a Mac computer’s internal storage with another Mac. - Allow file transfers between connected Mac computers using a or Thunderbolt or USB-C cable. - Startup Disk - Choose the device you want to use to start up a Mac. - This option is useful if you have multiple macOS installations. - Startup Security Utility - Manage security policies for a Mac. - Adjust security policies to allow any version of signed operating system software ever trusted by Apple to run. - Terminal - Change settings using the command line. - Use the - resetpasswordcommand to reset user passwords.
macOS Recovery logs
The recovery log contains messages logged by macOS Recovery. You can specify the types of messages to display:
- In macOS Recovery, choose Window > Recovery Log. 
- Click the Detail Level pop-up menu, then choose which messages to display: - Show Errors Only: Choose this option to display only error messages. 
- Show Errors and Progress: Choose this option to display error messages and progress messages. 
- Show All Logs: Choose this option to display all messages. 
 
You can also filter messages to search for specific text and save the recovery log to a file.
In macOS Recovery logs, you can view entries that give you insight into system activities such as network access, installation logs, Disk Utility activity, and more.
Here are a few common error messages you might encounter:
- APFS container corrupt: Could be a disk issue. (Consider Disk Utility or- diskutilrepair.)
- startosinstall failed with exit code 1: Invalid install target or issue with install media.
- Volume could not be mounted: Damaged volume.
Note: Depending on your organization’s data security and recovery policies, many of these issues might need to be escalated.
If you can’t access macOS Recovery
- What to look for: - Mac won’t start up or shows error symbols during startup. 
 
- What’s happening: - The Mac may have hardware issues or corrupted system files preventing normal Recovery access. 
 
- Steps to take: - Hold the power button for 10 seconds to completely shut down, then try the startup process again. 
- Check network connection for Internet Recovery options. 
- Use another Mac to create bootable installer if Recovery fails. 
- Contact Apple Support if hardware service may be required.