Value cannot be null.

Parameter name: source

stacktrace:

[ArgumentNullException: Value cannot be null.

Parameter name: source]

   System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source, Func`2 predicate) +2535654

   umbraco.BusinessLogic.User.GetApplications() +273

   umbraco.cms.presentation._umbraco.Page_Load(Object sender, EventArgs e) +64

   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +51

   System.EventHandler.Invoke(Object sender, EventArgs e) +0

   System.Web.UI.Control.OnLoad(EventArgs e) +92

   umbraco.BasePages.BasePage.OnLoad(EventArgs e) +14

   System.Web.UI.Control.LoadRecursive() +54

   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +772

Any idea where this null value comes from?

gogin thought the database does not shown any diference from other nodes.