Hello Amol

The error appears to be connected to session state. Some parts of the Episerver UI require session state. Do you have session state enabled?

David

Well, I believe Episerver edit mode is using ASP.net cookie based session to work , looking at the config I see <sessionState mode="InProc" timeout="60" /> , InProc mode is enabled.

Just to give a brief about the customization done in this case, an  HTTP handler is in place, which basically interupts request to media and routes it through a custom controller and view is rendered with the media embedded within it. So the pdf document is rendered on the browser but internally it is an Episerver page which is wrapping the media. This is done to achieve custom header when pdf is directly rendered on the browser. This Http handler expects IRequiresSessionState could this be related to this error?

Behavior is working just as expected in the view mode but in edit mode this error is coming up.

While writing this up ,I tried removing the dependency for IRequiresSessionState in the handler and it did the trick :) I was not getting the session error any more. Now I need to understand ,what was IRequiresSessionState doing in the handler. If nothing is being hampered ,I will commit the change . Job done...

Thanks David, once again

Perhaps. I celebrated way too early. With localhost , may be the error redirected so early that I couldn't recognize but with real domain in place. The error stayed in for a very long time for me to copy the error message content as well

Exception details: InvalidOperationException: The SessionStateTempDataProvider class requires session state to be enabled.

[InvalidOperationException: The SessionStateTempDataProvider class requires session state to be enabled.]
at System.Web.Mvc.SessionStateTempDataProvider.SaveTempData(ControllerContext controllerContext, IDictionary`2 values)
at System.Web.Mvc.Controller.PossiblySaveTempData()
at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.b__3(IAsyncResult ar)
at System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult)
at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.b__3(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.b__3(IAsyncResult ar)
at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

back to square one :(