I have found that the stock blades are not that good (in my opinion), you could have a dud blade that will not track. I got upgrades from miracle mart, GWS blades, they where much better to track, I think they where £12.00 for 3 sets ($24.00?? approx)

If you hold the blade at the root, twist it to track it, and try swopping the blades over to ensure its not something else causing the problem

Paul