A few weeks ago we started getting an impressive buildup of ice in our freezer:
Upon closer inspection, we discovered that the mysterious drip in the fridge, below the freezer was also due to creeping ice:
It turns out that although the freezer is "self-defrosting," the place the defrosted frost goes got clogged with too much ice and was thus frozen shut. Thus, the defrosted frost just hung around in the freezer, building up those cool ice crystals.
Fortunately, we have nice neighbors with a big fridge who let us store stuff while we did a massive defrost operation one Sunday. After all the ice finally melted (turned out to be a LOT) we dried the thing out using a custom-built rapid drying rig: