<?xml version="1.0"?> <configuration> <startup useLegacyV2RuntimeActivationPolicy="true"> <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/> <requiredRuntime version="v4.0.20506" /> </startup> </configuration>I still do not know, however, why this was necessary as the application does not have any reference to the old version.