External Boot

The ability to start a Mac from an external storage device containing a bootable operating system. Security settings may need adjustment on T2/Apple Silicon Macs.

What to Know

External Boot capability allows IT to troubleshoot Macs with corrupted internal drives, test clean OS environments without affecting the primary system, or run forensic analysis without modifying the internal disk. It’s essential for diagnosing whether problems are caused by the operating system, user configuration, or actual hardware failure. External Boot is also used to run older macOS versions for software compatibility testing when the internal drive has been upgraded to a newer, incompatible OS.

Common Scenarios

Enterprise IT: IT departments boot Macs from external drives to diagnose whether user-reported issues stem from software configuration or hardware defects. This helps determine if a full wipe and reinstall is necessary or if the problem lies with failing storage hardware.

MSP: MSPs use external boot drives when servicing Macs that won’t start from the internal drive, allowing them to access user data for backup before attempting repairs. It also enables testing Macs in a known-good OS environment without modifying the client’s existing system.

Education: School IT uses external boot drives to test lab Macs exhibiting strange behavior in a clean environment, determining if the issue is specific to the installed OS or a deeper hardware problem. This speeds up troubleshooting during busy classroom support hours.

In Addigy

While external booting happens outside of MDM control, Addigy admins can use Addigy to deploy instructions or scripts that guide users through the external boot process for troubleshooting. Once the Mac is repaired and boots normally, Addigy management automatically resumes, ensuring policies and configurations remain enforced.