I've had the same problem melting chocolate to dip strawberries in. I think our food has changed with the laws requiring that trans fat be taken out of a lot of things. I think maybe the amount of trans fat has been reduced in the chocolate chips. They may have substituted some other fat in the making of the choocolate chips. Who knows? I end up with a globby mess even using a double boiler. I have used Hershey's, Nestles's and Ghiradelli all with the same results.