If you are developing a WCF service with .NET 3.5 and come
across the following error message:
WCF Error: An error occurred while loading attribute
'XmlSerializerFormatAttribute' on method x in type
y
I have a very simple solution for you: make sure you have
installed .NET Framework 3.5 Service Pack 1 on all your
machines.
I have searched for hours for a solution to this error. It
appeared just on one single WCF call whereas all others were
working fine.
Finally I came across this
MSDN forums post that pointed me in the right direction.
So If you develop your software on 3.5 SP1 systems and then
deploying it to 3.5 systems without SP1, it's very likely you will
fix your problem by installing SP1.