If the vacuum pump runs without pulling or sealing, make sure you’ve allowed enough room at the top of the bag (refer to Quick Start Guide for instruction).Also, Check to see that the top of the bag is hanging over the Removable Drip Tray. Double-check that Gaskets are all clean and free of tear (both top and bottom), it is recommended to wipe with a wet cloth. If none of the above work, replace food into a new bag in case of hole or damaged bag. Make sure that the part of the bag that is fed into the window is not wrinkled. This can also occur if the machine seal bar has overheated. In this case, it will pre-seal the bag before all of the air has been removed. Wait several minutes for unit to cool down.