Your treadmill belt can be affected by a number of problems. It is vital to resolve belt issues prior to using the machine to prevent any harm to yourself or the treadmill. The owner's manual for your treadmill should provide tips for troubleshooting basic issues. However, there may be more complications with your treadmill that need to be addressed by a trained professional.
Most treadmill belt issues arise from an operational standpoint. This would include the belt being too loose, too tight or off center. A belt that is too loose results in slipping or drifting. A belt that is too tight will cause the belt to slow down or feel slow. A belt that is off center will also drift similarly to a loose belt. If your belt will not move it is likely related to a poor console cable connection. If the belt is running slowly and not due to the degree of tightness, the belt could be damaged from excessive wear. If you are experiencing issues with friction it is likely the belt needs lubrication.