Whenever I try to debug my Windows Phone 7 C# app, I get the following message in the Output window:
A first chance exception of type 'System.OverflowException' occurred in mscorlib.dll
A first chance exception of type 'System.OverflowException' occurred in mscorlib.dll
A first chance exception of type 'System.InvalidOperationException' occurred in Microsoft.Phone.dll
...And then, App.xaml.cs opens up in VS (still in debug mode, where I can't edit anything), and "System.Diagnostics.Debugger.Break();" is highlighted.
Why is this happening, how can I fix it, and how can I prevent it in the future?
Why it happened:
I had an image that was used in MainPage.xaml. This image's source's Copy to Output directory property was set to Do not copy, and as a result, the image failed to load and the app crashed.
How to Fix It:
Change the image in question's source's Copy to Output directory property to Copy Always from Do not copy.
How it can be prevented:
Don't fiddle with my image's Copy to Output directory properties.
...and what caused the System.OverflowException:
My low disk space [I think] is what is causing the System.OverflowExceptions, because these continued to pop up in my Output window after I fixed the problem. Read up on System.OverflowExceptions here.
来源：https://stackoverflow.com/questions/6741938/a-first-chance-exception-occurred-and-i-dont-know-why