Look in your Umbraco log (App_Data/Logs/UmbracoTraceLog.txt) for more details about the error, such as a stack trace.

I apologize. i do not know how to paste something from the text editor with the format still there

2014-11-18 14:04:10,685 [10] ERROR Umbraco.Core.UmbracoApplicationBase - [Thread 344] An unhandled exception occurred

System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.NullReferenceException: Object reference not set to an instance of an object.

   at Umbraco.Forms.Data.Storage.UserFormSecurityStorage.GetAllUserFormSecurity(Object userid)

   at Umbraco.Forms.UI.Pages.editFormsSecurity.OnInit(EventArgs e)

   at System.Web.UI.Control.InitRecursive(Control namingContainer)

   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

   at System.Web.UI.Page.HandleError(Exception e)

   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

   at System.Web.UI.Page.ProcessRequest()

   at System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context)

   at System.Web.UI.Page.ProcessRequest(HttpContext context)

   at ASP.umbraco_plugins_umbracocontour_editformssecurity_aspx.ProcessRequest(HttpContext context)

   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()

   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

2014-11-18 14:04:15,950 [10] ERROR Umbraco.Core.UmbracoApplicationBase - [Thread 291] An unhandled exception occurred

System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.NullReferenceException: Object reference not set to an instance of an object.

   at Umbraco.Forms.Data.Storage.UserFormSecurityStorage.GetAllUserFormSecurity(Object userid)

   at Umbraco.Forms.UI.Pages.editFormsSecurity.OnInit(EventArgs e)

   at System.Web.UI.Control.InitRecursive(Control namingContainer)

   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

   at System.Web.UI.Page.HandleError(Exception e)

   at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

   at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

   at System.Web.UI.Page.ProcessRequest()

   at System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context)

   at System.Web.UI.Page.ProcessRequest(HttpContext context)

   at ASP.umbraco_plugins_umbracocontour_editformssecurity_aspx.ProcessRequest(HttpContext context)

   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()

   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

I recommend you edit your posts to blank them out. It doesn't do much good to paste your entire trace log here. What you'll want to do is cause the error, then look at the last entry in your trace log. If that doesn't tell you exactly what's going on, you may then want to paste it here (just the relevant item, not the whole log).

the thing is, I got rid of the error by refreshing 3 times so its not a security error. Security was what I orignally thought but i dont think that is the issue

Could you set the customerrors to Off like it says currently in the error message (should just be an update of your web.config file) then we'll get to see the actual error

@tim, it is hard to reproduce. It just happens at random times. i will try in the staging site but so far i haven't had any problems. 

I cannot do that in production though.

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