Freezer interior icing up; thick frost on shelves, walls, and around door opening.

Safety: Unplug the freezer before defrosting heavy ice buildup to avoid water near live parts.

Steps:

• Inspect gasket: Check the door seal all around for tears, gaps, or hardened sections. Close a sheet of paper in the door and pull; resistance should be even all around.
• Adjust door: Ensure the appliance is level so the door closes by itself. Adjust leveling feet if necessary.
• Remove obstructions: Make sure baskets or food packages are not preventing full door closure.
• Defrost: Manually defrost the freezer by turning it off, leaving the door open, and placing towels to catch water. Use a hair dryer on low if needed; do not use sharp tools.
• Replace gasket: If the gasket is damaged or not sealing, replace it with a Bosch-specific door gasket. Warm the new gasket with a hair dryer to help it seat properly.