Freezer frost can be caused by the following conditions:
Your freezer door is not closing completely.
The freezer door gaskets are not attached to the door properly, are split or torn, or are not clean.
Your freezer is not being ventilated adequately.
You have food resting against the rear wall of the freezer.
The freezer air vent is blocked.
To prevent frost from forming in your freezer or on your freezer door, do the following:
Make sure that the freezer door closes completely.
Make sure that the door gaskets are attached properly to the door and that they are clean. Also, make sure they are sealing properly and are not torn or split.
Make sure there are no packages resting against the rear wall of the freezer.
Space your food out as much as possible to improve ventilation.
Make sure that the air vent in the freezer is not blocked.
If your door gaskets are torn or split, you should replace them.