FUSLOGW – Exception has been thrown by the target of an invocation (web.config) at ProvidersHelper.InstantiateProviders

If you see something like this in your event log , then your next step should be to check the assembly binding log. As you can see it’s a very generic error and doesn’t provide much details about the actual root cause, use this tool – http://msdn.microsoft.com/en-us/library/e74a18c4%28v=vs.71%29.aspx.

Exception information:
    Exception type: ConfigurationErrorsException
    Exception message: Exception has been thrown by the target of an invocation. (C:\Unify\Production-Bamboo\Content\5.1\TestWebApplication\web.config line 40)

Thread information:
    Thread ID: 4
    Thread account name: [somename]
    Is impersonating: False
    Stack trace:    at System.Web.Configuration.ProvidersHelper.InstantiateProvider(ProviderSettings providerSettings, Type providerType)
   at System.Web.Configuration.ProvidersHelper.InstantiateProviders(ProviderSettingsCollection configProviders, ProviderCollection providers, Type providerType)

 To setup this tool, you can follow this post –

http://stackoverflow.com/questions/2344317/fuslogvw-exe-tool-for-net-does-not-show-ui