If you do much with web services, this is a headache waiting to happen: in VS2005, there is a well hidden attribute in Project Properties titled "Generate serialization assembly." This option will allow your build process to automatically call out to sgen.exe and generate any types that your web service client needs to serialize...

The default setting for this option is "Auto" which the documentation is kind of vague about, but what others say (and I've also found) means that the serialization assembly will be created for "Release" config but not "Debug." Makes sense I suppose, as we are not all that concerned about performance in Debug mode.

But what can happen in Release mode is, the XmlSerializers assembly can throw a meaningless error and call stack when it encounters an error, but only when it is present... So this can make for very confusing deployment problems between Debug and Release modes.