EVERY time I run the descaler on my unit it stays in cleaning mode for hours, requiring adding more and more water until, usually, it eventually cycles through the rinse mode. I have wasted bottles of descaler trying to get it clean. I have seen others on the delonghi users facebook page with the same issue. Good luck getting a workable solution either. I have had several espresso machines over the past 30 years and have never been this frustrated by any of them.