Crash on editing a page

Topics: Administration
Aug 27, 2016 at 4:47 PM
I have a page that I have made many edits to over months without problems. Suddenly it crashes when I try to edit either from the page or from dashboard. I see this in the log:
,160 [47] Orchard.DisplayManagement.Implementation.DefaultDisplayManager - Default - ArgumentOutOfRangeException thrown from Action1 by System.Action1[[Orchard.DisplayManagement.Implementation.ShapeDisplayingContext, Orchard.Framework, Version=, Culture=neutral, PublicKeyToken=null]] System.ArgumentOutOfRangeException: Specified argument was out of the range of valid values. Parameter name: index at System.Linq.Enumerable.ElementAt[TSource](IEnumerable1 source, Int32 index) at Orchard.AuditTrail.Services.DiffGramAnalyzer.<Analyze>d__3.MoveNext() at System.Linq.Buffer1..ctor(IEnumerable1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable1 source) at Orchard.AuditTrail.Providers.Content.ContentAuditTrailEventShapes.<Discover>b__10(ShapeDisplayingContext context) at Orchard.InvokeExtensions.Invoke[TEvents](IEnumerable1 events, Action1 dispatch, ILogger logger) in z:\Builds\work\9f6cd39ff0f68f41\src\Orchard\InvokeExtensions.cs:line 17

The actual page is here:

I can edit other pages without problems. This page has only a simply HTML item on.

Any suggestions?
Aug 28, 2016 at 8:07 AM
This appears to be a bug in the DiffGramAnalyzer of the AuditTrail module.
You could disable the audit trail feature if this issue is blocking.
Perhaps you can find out how to reproduce this issue based on the page that is currently triggering this error?
For example, what happens if you export the "works" page and import it into a new, vanilla Orchard installation, with Audit Trail enabled?
If we can reproduce the issue, we can fix it.
Aug 28, 2016 at 6:21 PM
I first tried switching off all the Audit Trail events so it did nothing, but the page still crashed on Edit.
I then uninstalled the Audit Trail module, and now I can edit my page.
I'm afraid I don't have time right now to set up new Orchard site to help debug this, but happy to provide any other info about my setup if it helps track down the bug.