Popping or Cracking Noise - Columns

Possible Solutions

Contraction and expansion of the inside walls of the refrigerator may cause a popping or cracking noise, especially as the refrigerator cools down for the first time or defrosts.
This sound can also be heard when the ice is being ejected from the Ice Maker. The ice falling into an empty bucket can make a loud banging noise.
Both are part of normal operation.