What may be the cause of this? It happens every time when I build the app on either simulator or device.

Should i clean sth or reset my harddrive?

using High Sierra and Xcode 9.2


It is enough to open Xcode and it hums the same way.


The 2015 MacBook Pro uses a Solid State drive, so there's nothing on it that going to "hum."

In fact, the only mechanical component in the MacBook Pro (besides the keys and LCD hinge, of course) is the fan. The fan may be spinning up due to the increased load put on the CPU. Additionally, it may be clogged with dust or the bearing is simply defective.

Try giving it a cleaning and see if the problem goes away. There's no need to "reset" your drive as this would have no effect.

  • So I try to clean it up and let you know if it helped;) I have the same second macbook and it doesnt work like that;) – Bartłomiej Semańczyk Apr 13 '18 at 11:55
  • 2
    You could also try running xcode with the bottom cover off and when the fan starts, stop it with your finger. If the hum stops - it's the bearing. – Allan Apr 13 '18 at 11:58
  • Also xcode compiling takes a lot of course so the fans will make more noise when that happens. – user151019 Apr 13 '18 at 23:36

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