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Macintosh POST Beeps Defined – Part 3

Intel-based Macs such as the iMac, Mac mini, MacBook, MacBook Pro, and Mac Pro rely on a combination of tones and blinking LEDs to display Power On Self Test (POST) error codes. If the computer detects no SDRAM (Synchronous Dynamic Random Access Memory, also referred...

Macintosh POST Beeps Defined – Part 2

What do the beeps during the Power-On Self-Test (POST) mean? This test runs whenever the computer is powered on after being fully shut down (the power-on self-test does not run if the computer is only restarted). When a fault is detected during the Power-On Self-Test,...

Macintosh POST Beeps Defined – Part 1

What do the beeps during the Power-On Self-Test (POST) mean? When a fault is detected during the Power-On Self-Test, you will not hear the normal startup chime. Instead, the system will beep as explained below. 1 beep = No RAM installed/detected 2 beeps = Incompatible...