Fans run at high speed at initial login screen

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Level 1

18 points

Fans run at high speed at initial login screen

Hello Apple Community,

I am experiencing an issue with my fans running at high speed at the initial login screen. After login the fans slowly quiet down. I can then logout and the fans will stay silent. If I reboot the login screen returns and the fans begin ramping up to full speed again. It sat like this for a bit, didn't put itself to sleep, nor jumped to the screensaver, and discharged the battery very rapidly. It's not normal and I haven't found a fix, any ideas?

Side note: I did perform a clean install of high sierra and the issue wasn't resolved.

MacBook Pro 15in mid-2017 w/ touch bar

macOS High Sierra 10.13.2

Core i7

2.9GHz

16GB

Radeon Pro 560

MacBook Pro TouchBar and Touch ID, macOS High Sierra (10.13.2)

Posted on Dec 22, 2017 10:54 PM

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Answer 1

Top-ranking reply

tdormady23 Author

Level 1

18 points

Dec 25, 2017 1:36 AM in response to John Galt

Hi John (and all that find this post)

Alright so this issue "might" stem from an 'encrypted' file vault issue during the setup and upgrade to high Sierra. I got a scheduled apple store visit today and the tech suspected encrypted file vault causing the fuss. (I assume he had seen this before).

After reinstalling the OS back to Sierra we ran a test user account and let it sit at the login screen for quite awhile. No more high fan speed and no more over heating. We jumped in to Single User mode removed the test user after the troubleshooting was complete.

I got home and set up the system like you would for the first time. I started on Sierra and let all the updates come in first, rebooted, then ran the upgrade for High Sierra and it seems to be fine now. I rebooted the system and let it sit at the initial login screen, waited for several minutes and the fans were fine, it was running as it should without the excessive fan speeds and overheating it was suffering from before.

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Answer 2

dominic23

Level 10

84,018 points

Dec 23, 2017 7:19 PM in response to tdormady23

Reset SMC, if you have not already.

Reset SMC. Choose the method for “If the battery is non-removable”.

https://support.apple.com/en-us/HT201295

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Answer 3

John Galt

Level 10

155,702 points

Dec 23, 2017 6:49 PM in response to tdormady23

Nothing wrong there either.

Since you already accomplished everything anyone could reasonably expect you to accomplish toward isolating the problem, and since your Mac is likely to be well within its original one year warranty period, I suggest contacting Apple for a thorough diagnosis.

After examining it I am nearly certain they will declare it the picture of Mac health. That's not a waste of time though. If there is something wrong with the hardware that could become exacerbated at some time in the future, you will have established a case history that can be called upon when required.

To get that started, click Contact Support.

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Answer 4

John Galt

Level 10

155,702 points

Dec 23, 2017 3:57 PM in response to tdormady23

If you need help interpreting it, you may post a screenshot of the Activity Monitor window, similar to that shown in that Apple Support document. To learn how to capture, edit (if necessary) and post a screenshot to this site please read the Appendix in Writing an effective Apple Support Communities question.

If you are unable to correlate the fan activity to any particular app or process, and if an SMC Reset doesn't help, then the cause is likely to be cooling system inefficiency—a hardware concern that may be easily fixed. That particular problem will manifest in a runaway process named kernel_task. Read about that here: If kernel_task is using a large percentage of your Mac CPU - Apple Support.

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Answer 5

John Galt

Level 10

155,702 points

Dec 23, 2017 3:41 PM in response to tdormady23

Please readApps can affect Mac performance, battery runtime, temperature, and fan activity - Apple Support.

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Answer 6

tdormady23 Author

Level 1

18 points

Dec 23, 2017 3:42 PM in response to dominic23

Hello Dominic23

I followed the instructions on the SMC reset to no avail. The system fans still resume to full speed shorty after starting the system. I have to login first, then fans begin to settle down to a reasonable level. I am wondering if it was the update that caused the issue. Thanks for taking the time to respond.

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Answer 7

tdormady23 Author

Level 1

18 points

Dec 23, 2017 3:50 PM in response to John Galt

Hello John,

Thanks for the post in response to my question. So, it's the weirdest thing after the system boots and the login screen comes up, if you let it sit without logging in, about 30 seconds to a minute the fans are at full blast. They actually whistle, pretty loudly. Well, I'll keep hunting down a solution. Thanks for taking the time.

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Answer 8

tdormady23 Author

Level 1

18 points

Dec 23, 2017 5:25 PM in response to John Galt

I'll check it. Is there a way to launch the activity monitor at boot? I'll perform a reboot and let the fans get up to speed and login, open activity monitor quickly, and grab a screenshot and see if anything looks different. Soon as I login you hear the fans start to decelerate and calm down. Thanks for you help on this issue.

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Answer 9

tdormady23 Author

Level 1

18 points

Dec 23, 2017 4:59 PM in response to John Galt

Hello John,

Here's the screenshot I think we are looking for.

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Answer 10

John Galt

Level 10

155,702 points

Dec 23, 2017 5:10 PM in response to tdormady23

I can't find anything wrong with that. Nothing is obviously amiss. See if you can catch another screenshot at a time when the fan runs audibly loud.

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Answer 11

John Galt

Level 10

155,702 points

Dec 23, 2017 5:30 PM in response to tdormady23

You can make it a Login Item: Open items automatically when you log in on Mac - Apple Support. You really can't do anything other than that, since you can't do anything until you log in.

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Answer 12

tdormady23 Author

Level 1

18 points

Dec 23, 2017 5:38 PM in response to John Galt

I rebooted and let it sit for several minutes, fans were running at full tilt, nice and loud, cpu gets pretty hot, I could feel it. Logged in quickly and grabbed this for the record.

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Answer 13

tdormady23 Author

Level 1

18 points

Dec 24, 2017 12:33 PM in response to John Galt

Hello John,

Thanks for all the help. I appreciate your time and experience.

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