Hi Guys,

We had an issue on our production website which caused the home page to stop working, and after looking at the exception it looked like a simple problem of a property being null and the code not handling it.

So I rolled back the Umbraco database to a point earlier in the day, the site came back online.

However I took a back up of the 'broken database' and restored it locally so I could step through the code and find out exactly where it was breaking.

After restoring the database locally I logged in to Umbraco to find that pretty much every node in the content tree had all the tabs defined on the document type missing.

I could only see the Properties Tab, everything else had vanished. So I navigated to the document types and every time I click on a document type I get this exception:

    Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 


[NullReferenceException: Object reference not set to an instance of an object.]
   umbraco.controls.GenericProperties.GenericProperty.UpdateInterface() +255
   umbraco.controls.GenericProperties.GenericProperty.Page_Load(Object sender, EventArgs e) +42
   System.Web.UI.Control.OnLoad(EventArgs e) +105
   System.Web.UI.Control.LoadRecursive() +67
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.Control.LoadRecursive() +161
   System.Web.UI.<LoadRecursiveAsync>d__246.MoveNext() +639
   System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() +31
   System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +60
   System.Web.Util.WithinCancellableCallbackTaskAwaiter.GetResult() +32
   System.Web.UI.<ProcessRequestMainAsync>d__523.MoveNext() +6641

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3160.0

I'm not sure why this has happened, but It seems like the database has become corrupt in some way. Has any one got any ideas of how/why the database could have become corrupt.

Id really like to get to the bottom of why this happened.

Thanks in advance.