Q: Macbookpro Fan suddenly spin fast and loud whereas it's not hot

A new Mac comes with 90 days of free tech support from AppleCare.

AppleCare: 1-800-275-2273

Try resetting SMC.

Reset SMC.     http://support.apple.com/kb/HT3964

Choose the method for:

"Resetting SMC on portables with a battery you should not remove on your own".

Best.

I have seen this be mentioned as a workaround several times. It doesn't work for this issue. I bought an early 2015 that had this problem and swapped it for a new one. The new one has the same problem. SMC resets dont work. Apple store doesn't see anything wrong with it. The fan rev up happens out of nowhere so its hard to diagnose and even harder to demonstrate to people at the apple store. It's frustrating that this is the only answer people ever offer up.

I spent several hours -- not to say days -- on researching of this problem (tried different Macs (about 15-20) at different stores, simulated various load and working conditions). Here is what I have got:

It happens on every Macbook Pro 13'' 2015.

Talking about the reasons:

One may notice that it happens only when your Mac is not connected to the power source. Sudden fast spinning never happens when your Mac is on charge or connected to the adapter.

I analyzed temperature sensors data (via TG pro or iStats) and came to conclusion that it is connected to the frequency with which SMC reads data from temperature sensors. This frequency is much slower when Mac is working on battery, so SMC is not able to detect temperature raise immediately, and, when working on battery, fans turn on only when CPU reaches temperature of about 95 degrees celsius.

Maybe, Apple engineers intentionally lowered sensor update frequency while working on battery in order to save battery life and to get this enormous numbers of 10+ hours on battery.

In most working conditions this behaviour is just fine, because on Mac model fans are completely off during normal operation, and came on only when it is needed. Yes, it is somewhat frustrating if your fans are suddenly come on when your Mac is working on battery and under heavy load , but it is completely harmless for your computer.

EXCEPT that it comes on when it is plugged in as well

It just happened to my Macbook Pro 13" Early 2015, out of nowhere!   Cool room, the computer itself was cool as well, very light load (I have Activity Monitor permanently on the Dock showing the CPU usage history).  It freaked me out!  I was afraid my month-old Macbook Pro was gonna self-destruct or something like that because I have never heard the fan being so loud and working so hard. Fortunately, the fan eventually slowed down gradually and then stopped.   Apple should investigate and fix this.  This is not normal.

Along with Mavericks 10.10.4 update, Apple released the SMC update for MBP 13'' that fixes this issue. You can check your SMC version (About This Mac -> System Report), after update it should be 2.28f7 (talking about MacBook Pro Retina 13'' 2015). If you have 2.28f6 or earlier, just update everything related to system via App Store. New SMC version solves that problem.

EXCEPT that I have a brand new MacBook Pro which is 2.28f7 and it's doing it. Not overheated and not working hard, just annoying as I use it mainly to record music so a loud fan in the background is unacceptable.

This is happening to my macbook pro 13 i7 16gb ram too. bought on Apr 2015. I found the fan start screaming when i do watch amazon instant video or heavy stuff like starting Virtualbox with hadoop(in this case mac gave up... i have kill the virtual box instance, sad to see inspite of having high specs and very high range this mac cant handles these)

Hi, I also have this psame roblem since 5 days on my macbook pro 13' that i bought in december 2013.

Out of nowhere and for no reason (no program was on, just google chrome) the fan started buzzing and going like crazy without being hot.

I have tried restarting the smc, doing the apple diagnostics, i have installed the new software "el capitan" but the fan noise won't stop.

This  Friday I have an appointment at the genius (Apple store) .

My questions are:

- how much time did it take to solve this?

- what is the solution Apple gave you?

thank you so much for your help!

fiorella

This happened to me for DAYS until I realized it was HP trying to print to a printer I was no longer near. I cancelled the print cue and it cleared right up. Check your printer cues.

That was is. Same issue mate. Cleared the Queue problem solved. Thanks a lot!

Thanks! that was the problem and it stopped immediately after clearing the queue!

I think Steve Jobs is dead and so is the soul of the APPLE, I feel it, reading the Mac forums; bugs, OS Captain etc. :-(

I just purchased my Macbook pro 15 inches retina display, i7 and the best processor out there. It turns out that, it is my fourth day and the macbook pro gets really hot and the fans start roaring and i am playing nursery rhymes for my girl on you tube.

Reading the answers, I think, I have made a stupid choice buying a mac. Looks like there is no solid solution out there.

I am considering returning it and getting a refund.

this happened to me today with my rMBP 13" (early 2015), and it's only 2 weeks old.

what i did was i closed the lid until it sleeps. after a couple of seconds i re-opened the lid and the noise was gone.

i'm monitoring it and will post again on this thread once the issue recurred.