Each will test memory differently and some may miss a problem that another can detect. But, as I say, there are many of them just check the Mac App Store and search for RAM. You can also get a graphical wrapper for memtest, called Memtest, which is run from the Terminal command-line.

In addition to Apple’s testing suite, there are plenty of third-party memory-testing utilities. If everything is OK, you’ll see a message that states all tests passed and no problems were found. If the hardware test finds any faulty memory, it will list the faulty memory addresses. Note that, if you have formatted your hard drive and reinstalled OS X, then the built-in hardware tests may have been wiped however, you can still load them from the Internet by holding the Option-D key combination (as opposed to just D) at startup when you hear the boot chimes. Release the keys.On newer Macs, the tests run automatically when the utility is invoked it appears with a gray background instead of blue. Hold the keys down until the computer restarts and you hear the startup sound for the second time.Ħ. Press and hold the Command-Option-P-R keys.ĥ. You will need to hold these keys down simultaneously in step 4.ģ. Locate the following keys on the keyboard: Command, Option, P, and R.

Hold these keys and the power button for 10 seconds.ģ If you have a MacBook Pro with Touch ID, the Touch ID button is also the power button.ĥ Press the power button again to turn on your Mac. How to fix MacBook beeping 3 times Try resetting the SMC Ģ After your Mac shuts down, press Shift-Control-Option on the left side of the built-in keyboard, then press the power button at the same time. If the problem persists, visit an Apple professional immediately or contact Apple Support directly. You may have recently replaced or just upgraded the RAM memory on your MacBook Air or MacBook Pro computer and it was not installed properly. If your MacBook Air or MacBook Pro computer is broadcasting 3 successive beeps at intervals of approximately five seconds, it means that RAM memory did not pass the data integrity check. The beeping indicates that there is an issue with your notebook’s RAM. Why MacBook beeping 3 times and won’t startup? Why MacBook beeping 3 times and won’t startup?.

Macbook pro 3 beeps startup