Roller doors are an area of risk for forklift operations; collisions with them are frequent. If a forklift hits a roller door, it can bend the door or pull it off its tracks. This might mean that it’s impossible to secure the building at night, plus it’s an expense that a company doesn’t need.
Best practice is to raise them fully and also ensure that nobody is operating a forklift with the forks raised. The tendency is for people to open it just as much as they need for themselves because roller doors are slow to open, particularly if they are done manually with a chain. If there are two roller doors, having one lower than the other is a risk because the forklift drivers, who are focusing on driving will forget. The same applies for trucks driving in to drop off goods, for scissor lifts, and walkie stackers with masts.
If a forklift hits a roller door at speed, it can bend the backrest and forks, and damage the freight, too. Hitting it backwards often tips the forklift over forwards. Awareness of this is something that should be covered in any internal forklift training and induction.