What setting/time, please? I have a package that has become a rock. I had two like that and put one into the oven on a cookie sheet after heating to 250 and then turning the oven off. After an hour, I could at least break off chunks, which I then had to put in the food processor in order to get it granular. It was a hassle, so if there is an easier method, please share with detail.
When I have a bag of sugar that’s gone hard, I break it up. First I wrap the paper-wrapped sugar package in one or two layers of plastic - typically plastic grocery bags. Once it’s wrapped, I drop it onto a concrete surface a few times until it breaks up into more manageable pieces. There will still be chunks. I filter the broken up sugar through a mesh strainer. The smaller pieces can usually be crushed easily between fingers once the big block has been bashed around a few times.
For brown sugar, I microwave it on regular power in 30 second intervals until it is soft enough to break apart. I would assume you could do the same with white sugar.