Today one of my colleagues tried to start a newer version of one of or .Net tools on her Win7 computer which was just copied from deployment share.

The app didn’t started, only Windows Error Reporting was doing something on the systray. In the Eventlog there was an error 22 with CLR20r3 and mentioning a FileLoadException. P4’s value: PresentationFramework. Short check about installed frameworks, etc.: everything seemed to be fine. Nothing useful was found in generated WER file either.

The tool was running well on other’s machine. What happened with her’s?

In the app’s .config file there were custom app settings in the appSettings section that’s why we keeped the original file from previous installation. The problem was that in .config there was an assemblyBinding section with a bindingRedirect too:

<configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="AnAssembly" publicKeyToken="123123123123" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-1.0.33334.0" newVersion="1.0.33334.0" />
      </dependentAssembly>
     ...

The new code had a newer version of the AnAssembly which wasnt used because of the bindingRedirect above! The new .config had the updated version numbers, but we overwrite it with the previous version of file because we would like to keep the correct appSettings values. It is very handy to use the appSettings section in the .config but it is a bad idea because of framework configuration is keeped in the same place. Keeping it separately seems better idea.

PS.: What about PresentationFramework in the P4 value? Completely missleading info…