My mac won’t start and only makes beeping noises.

Q: My mac won’t start and only makes beeping noises. What are they and what do they mean?

A: Here’s what Apple says:

Products introduced after October, 1999 use a revised set of power on self-test beeps during startup. This article describes each one.

 

Products Affected

Portable Computers, Desktop Computers

The power on self-test resides in the ROM of the computer. This test runs whenever the computer is turned on after being fully shut down (the power-on self-test does not run if the computer is only restarted).

 

If a fault is detected during the test, you will not hear a normal startup chime. Instead, the system will beep as explained below. If you experience one of these beeps, you may call your Apple Authorized Service Provider for additional troubleshooting assistance.

 

1 beep = no RAM installed

2 beeps = incompatible RAM types

3 beeps = no good banks

4 beeps = no good boot images in the boot ROM (and/or bad sys config block)

5 beeps = processor is not usable

 

In addition to the beeps, on some computers the power LED will flash a corresponding number of times plus one. The LED will repeat the sequence after approximately a 5-second pause. The tones are only played once.

 

To sum up; it’s usually a RAM (memory) problem or the actual sockets the RAM modules are in. Sometimes reseating the RAM can make the problem go away.