My deep freeze creates a vacuum holding the lid seems to do it if you go back 10 min after opening it up.
But if you wait a day u can open it up easily. Its a smaller model 3' X 3' X 3'. Was wondering if the small size was the reason...if it was a large one would the larger door and gasket be easier to break the seal on the gasket. Its always done this...just curious why. All other deep freezes i have opened i did not notice this.