Invalid contract attribute for IMetadataExchange

Question

I have upgraded a WCF Service to .NET Framework 4.5. After doing so I noticed a blue squiggly line around the IMetaDataExchange in the host config file.

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Answer 1

Perhaps not the answer for the OP, but others with this problem should check that [ServiceContract] is declared for the interface of your services, because this produces the exact error.