I followed Apple's instruction to reset PRAM ("Press and hold the Command-Option-P-R keys before the gray screen appears.") and the only thing that happened was that my Mac rebooted repeatedly until I stopped holding the short-cut. After releasing the keyboard OS was loaded but without any startup sound and my original problem remained (see Original problem)

I found out that not being able to reset PRAM may be caused by the user password, so I tried to disable the password request but this did not work either. This seems to be because of FireVault which I deactivated a couple of hours ago. My system is still encoding so it might take another couple of hours until I can see whether this approach was useful.

Does anyone have another advice?

Original problem: No sound, no micro

My MacBook Pro (2.4 GHz Intel Core 2 Duo, Mac OS X Lion 10.7.5 (11G56)) was on stand-by all the night. When I opened my Mac this morning I had no sound and my micro did not work either (A call via skype failed (I could not hear anybody and they did not hear me) but the camera worked. I cannot hear music via iTunes nor any other application. Also I cannot hear the click sound when one tries to turn up volume.). Therefore I thought resetting PRAM would be the solution but I failed in doing so as described.

  • 1
    From what you described it sounds like you successfully reset the PRAM. While holding the command+option+P+R keys your Mac will reboot continuously until you let go. Typically I'll hold them until I hear the Mac chime twice, which is an indicator that NVRAM is also reset. A failed PRAM reset would be indicated by the Mac not rebooting, instead continuing to an Apple logo or password prompt. – Mr Rabbit Apr 7 '14 at 18:51
  • You might try an SMC reset. For your Mac you would shutdown as normal, remove the battery, press and hold the power button for 5 seconds, reinstall the battery and connect to power, then power on as normal. Apple has a help document on this here, you would follow the "Mac portable with battery you can remove" instructions - support.apple.com/kb/ht3964 – Mr Rabbit Apr 7 '14 at 18:53

Based on what you said, it looks like your PRAM did reset. I usually let it go 3 times before letting my Mac restart. The problem then lays outside of the realm of PRAM.

Have you tried checking the inbuilt application "Audio MIDI Setup" to confirm what the Inputs and Outputs are? And are the Inputs and Outputs turned up?

If that doesn't work, have you tried doing a SMC reset? Those usually deal with the problems relating to system software.

| improve this answer | |

I never heard of PRAM resetting until my MBP started running super slow and took over 2 minutes to boot up. I found this thorough article about PRAM Reset on nextweb, which helped me greatly. It has instructions for different MBP models and additional resetting instructions to consider. Satisfactory performance since.

I pair the PRAM reset with the SMC Reset. So far performance is great. Though I find I have to reset often whenever I work on major projects in Photoshop and Illustrator. Hope this helps!

| improve this answer | |

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .