Why does my application work fine in release mode but crash in debug mode?

The most common reason is a library mix-up. When you build your application in debug mode (that is, with _DEBUG defined), the compiler uses a debug version of the memory allocation and deallocation functions (see this MSDN page). When using Ice, memory is sometimes allocated by Ice and deallocated by the application (or vice-versa). You cannot allocate memory with the release version and deallocate this memory with the debug version, therefore it is critical that your application and the Ice libraries linked with your application use the same heap allocation functions.

The binary Ice distribution on Windows includes both debug and release libraries: use the import libraries with a d suffix (such as iced.lib and iceutild.lib) to link with the debug DLLs.