I bought this ladder about 8 to 10 years ago to use in my business.  Thank goodness I haven't needed it that often as after only a few uses, the plastic sleeves that align the sections started unseating causing the ladder not to be able to fully "nest".  You can take off the feet at the bottom and pull the sleeves out until you get to the one that has unseated and gotten misaligned, reseat it, which is not always easy, replace all the others above, making sure that each one of them is properly seated, and it will then become useable again for a few more times, if you're lucky.