Sometimes strange things happen. It happened to me, I figured it was a fluke. But last week it happened to my co-worker too. Weird right? Everything was working great with my VS Solution including a Silverlight App. It isn’t new and I’ve debugged it many times. But for some reason, no matter what I did, the debugger seems to be ignoring my breakpoints. At first I thought that maybe the code wasn’t getting called, but it sure seems like it was getting called. If you find yourself in this predicament, here’s all you need to do. Go to the Property Pages of your Web App (the application that hosts the Silverlight). You get there by right clicking on the Web Application in the Solution Explorer and select Properties. Then choose the “Web” tab and you’ll see the one below. If debugging doesn’t work, the “Silverlight” checkbox is probably not checked! I’m not sure how this setting gets reset, but at least it is easy enough to fix.