Friend's macbook making a crunching noise while on.

[nickthemajin]

Sounds like really loud coil whine.

What do you guys think?

 

[snaky69]

Could be a fan crapping out.

 

[T5BRICK]

It's a retina MacBook Pro, there isn't really an option for moving parts besides the fan.

 

[Fishrrman]

The only moving part is the fan, so I'll guess that that's the problem...