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Since I upgraded to Mountain Lion, my Macbook Air 13" (Intel Core i5) has become extremely noisy.

The CPU cooler starts going crazy after just 10-20 mins of internet surfing. Before I could only make it loud and crazy when I used Xcode or similar 'heavy' apps.

What I can see from the Activity Monitor, is that the securityd process is consuming 12-15% CPU at all times:

Screenshot of Activity Monitor

Does anyone have a workaround to solve this?

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A good first step is to run Activity Monitor during the noisy periods. Sort by CPU usage descending - is a particular app or process using an unusual amount of CPU time? This is typically what pushes my Air's fan into overdrive (and the Safari Web Content process is often the culprit...) – Dan J Aug 28 '12 at 23:09
I see that the securityd process is constantly consuming 12-15% CPU -- I presume that it's something way out of my control... – MartinHN Aug 30 '12 at 10:00
up vote 2 down vote accepted

I had similar on my late 2008 MBP 15" after upgrading to Mountain Lion.

I found a post about resetting the SMC controller (system management controller) to solve this and it worked a treat for me. I have a removable battery on my MBP so the process was a little different to unibody mbp's where you can't easily get at the battery. It was basically:

  1. remove power cable and battery,
  2. hold the power button for 5 seconds.
  3. Power up normally and see if it worked.

For portables without a user-serviceable battery (like your Macbook Air):

  1. plug in the power cable to mac and a power source,
  2. press the (left side) ⇧ ⌃ ⌥ keys and the power button at the same time,
  3. release all the keys and the power button at the same time.
  4. Power up normally.

Give it a try - there are plenty of posts on the web on how to reset it. Mine is quiet as a mouse now

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Looking good so far -- the securityd process is not taking up huge amounts of CPU time after doing the SMC reset. – MartinHN Aug 30 '12 at 18:25

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