DIAGNOSIS The blade assembly is not engaging with the drive socket in the pitcher base. This is almost always due to incorrect assembly or a worn component.
FIX 1. Remove the blade assembly from the pitcher. 2. Inspect the black plastic drive socket on the bottom of the pitcher base for any broken or missing teeth. 3. Align the protruding tabs on the blade assembly with the notches inside the pitcher. 4. Press down firmly and rotate the blade assembly clockwise until it clicks and locks. You should not be able to pull it straight out.
IF THAT DIDN'T WORK If the blade assembly still spins freely, the locking mechanism on the blade assembly itself may be damaged. The plastic tabs that engage the pitcher can wear down or break. This requires replacement of the blade assembly (part NJBLADESS151).
HEADS UP Never force the blade assembly to rotate counter-clockwise to remove it. Always press down and rotate clockwise to lock, then lift and rotate counter-clockwise to unlock, as per the embossed arrows.