Mac OS X Startup Sequence & Error Codes and Symbols

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Faculty/Staff

Researcher

Student

GTF

Overview

The following is an overview of the startup sequence, error conditions, and behaviors for all Intel-based Macintosh systems.

For any other issues besides these errors and symbols, and you're still having problems starting up your Mac, please refer to http://support.apple.com/kb/TS1411?viewlocale=en_US

Startup Sequence stage	Event
Power On	Boot-ROM/RAM check is initialized
BootROM-POST	Black screen, power LED on: POST or BootROM failure Flashing power LED once per second: bad RAM or no RAM Three flashes, a pause, and three more flashes (occurs continuously): marginal RAM
BootROM-EFI	Boot chime
Boot EFI	Metallic Apple: found boot.efi Circle with slash: could not load boot.efi, or some other issue Flashing globe: looking on the network for booter/kernel on netboot server Metallic Apple with spinning earth below: found booter/kernel on netboot server Broken Folder that blinks: no bootable device or operating system was found
kernel	Grey screen with Metallic Apple and spinning gear
launchd	Blue screen
loginwindow	Login window appears
User Environment Setup	The text "Logging in..." appears in login window along with a progress bar. Upon successful login, the Desktop and Dock appear.