iMac’s fan running non-stop, loudly

iMac’s fan running non-stop, loudly,…: Apple Support Communities. I had a friend who had the same problem with the iMac fans running very loudly after an SMC reset. Following rkaufmann87 instructions below worked perfect for me.

Sometimes you have to reset the SMC 2-3x for it work and because different Macs uses different processes to reset the SMC I’m going to post the procedure for an iMac. Please read the instructions carefully.


  • Shut down the computer.
  • Unplug the computer’s power cord and all peripherals.
  • Press and hold the power button for 5 seconds.
  • Release the power button.
  • Attach the computers power cable.
  • Press the power button to turn on the computer.


  • Shut down the computer.
  • Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
  • Turn on the computer.
  • Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
  • Hold the keys down until the computer restarts and you hear the startup sound for the second time.
  • Release the keys.

iMacs are great tools but becoming more limited in upgradability all the time. Sometimes your iMac gets stuck in an endless loop. One cool way of speeding up the speed of iMacs has been Fusion Drive. There are some other great uses of iMacs. Of course there is always iMac, iSaw, iConquered. I never bought an iMac because I always preferred the laptop but I was tempted many times. The problem was just a matter of space. Desktop systems need a steady desk, good chair and limited in portability. It was just so convenient to have access to my data wherever I am. Now with cloud services I would get a iMac and sync everything online. More people seem to be buying secondary systems once they use web service providers.

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Interested in technology, loves life.