Opening & Closing Lid

[AceC]

I closed the lid on my MBP, forgot something, and then opened it right back up during its transition to sleep mode. When opened, it made this weird screechy noise, but all is well now.

Why did that happen, and should it be concerning?

 

[Raunien]

Did it sound like the disk drive? If it is the disk drive whirring, then it might have something with hibernation. I changed my hibernation settings after experiencing the disk drive sound and it no longer occurred.

See https://forums.macrumors.com/threads/1480259/

 

[simon48]

It could only be a fan or a HD (if you don't have an SSD) as those are the only moving parts.