The main reason this was happening was because I had a mismatch in the types I was trying to Serialize and Deserialize. I was Serializing ObservableCollection (of Group) and deserializing a business object – Groups which inherited ObservableCollection (of Group).
And this was also part of the problem…
From – http://social.msdn.microsoft.com/Forums/en-US/asmxandxml/thread/9f0c169f-c45e-4898-b2c4-f72c816d4b55/
This exception is a part of the
XmlSerializer’s normal operation. It
is expected and will be caught and
handled inside of the Framework code.
Just ignore it and continue. If it
bothers you during debugging, set the
Visual Studio debugger to only stop on
unhandled exceptions instead of all
exceptions.