It makes a difference how a freezer, refrigerator or icemaker is transported. If the appliance is moved on its side or back, it must stand upright for 24 hours before being restarted. If the unit is transported upright, it may be restarted immediately.  Lubricating oil for the refrigeration compressor can flow out of the crankcase, if the unit is not upright. Running the unit without oil can ruin the compressor, which is a major problem.