diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Controllers/AdminController.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Controllers/AdminController.cs
index ef06f48f5..dd2ee5cd4 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Controllers/AdminController.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Controllers/AdminController.cs
@@ -52,8 +52,7 @@ namespace Orchard.AuditTrail.Controllers {
             var eventDescriptors = eventDescriptorsQuery.ToDictionary(x => x.Event);
             var recordViewModelsQuery =
                 from record in pageOfData
-                let descriptor = eventDescriptors.ContainsKey(record.FullEventName) ? eventDescriptors[record.FullEventName] : default(AuditTrailEventDescriptor)
-                where descriptor != null
+                let descriptor = eventDescriptors.ContainsKey(record.FullEventName) ? eventDescriptors[record.FullEventName] : AuditTrailEventDescriptor.Basic(record)
                 select new AuditTrailEventSummaryViewModel {
                     Record = record,
                     EventDescriptor = descriptor,
@@ -76,7 +75,7 @@ namespace Orchard.AuditTrail.Controllers {
                 return new HttpUnauthorizedResult();
 
             var record = _auditTrailManager.GetRecord(id);
-            var descriptor = _auditTrailManager.DescribeEvent(record.FullEventName);
+            var descriptor = _auditTrailManager.DescribeEvent(record);
             var detailsShape = _displayBuilder.BuildDisplay(record, "Detail");
             var viewModel = new AuditTrailDetailsViewModel {
                 Record = record,
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentPartSettingsUpdatedEventShape.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentPartSettingsUpdatedEventShape.cs
index 6c147b6ad..2d9a85201 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentPartSettingsUpdatedEventShape.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentPartSettingsUpdatedEventShape.cs
@@ -3,8 +3,10 @@ using Orchard.AuditTrail.Helpers;
 using Orchard.AuditTrail.Shapes;
 using Orchard.ContentManagement.MetaData.Services;
 using Orchard.DisplayManagement.Implementation;
+using Orchard.Environment.Extensions;
 
 namespace Orchard.AuditTrail.Providers.ContentDefinition.Shapes {
+    [OrchardFeature("Orchard.AuditTrail.ContentDefinition")]
     public class ContentPartSettingsUpdatedEventShape : AuditTrailEventShapeAlteration<ContentPartAuditTrailEventProvider> {
         private readonly ISettingsFormatter _settingsFormatter;
         public ContentPartSettingsUpdatedEventShape(ISettingsFormatter settingsFormatter) {
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypeFieldSettingsUpdatedEventShape.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypeFieldSettingsUpdatedEventShape.cs
index db7a7a9e9..6d2b64dda 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypeFieldSettingsUpdatedEventShape.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypeFieldSettingsUpdatedEventShape.cs
@@ -4,8 +4,10 @@ using Orchard.AuditTrail.Shapes;
 using Orchard.ContentManagement.MetaData.Models;
 using Orchard.ContentManagement.MetaData.Services;
 using Orchard.DisplayManagement.Implementation;
+using Orchard.Environment.Extensions;
 
 namespace Orchard.AuditTrail.Providers.ContentDefinition.Shapes {
+    [OrchardFeature("Orchard.AuditTrail.ContentDefinition")]
     public class ContentTypeFieldSettingsUpdatedEventShape : AuditTrailEventShapeAlteration<ContentPartAuditTrailEventProvider> {
         private readonly ISettingsFormatter _settingsFormatter;
         public ContentTypeFieldSettingsUpdatedEventShape(ISettingsFormatter settingsFormatter) {
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypePartSettingsUpdatedEventShape.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypePartSettingsUpdatedEventShape.cs
index 7240b21a5..abf4e0911 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypePartSettingsUpdatedEventShape.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypePartSettingsUpdatedEventShape.cs
@@ -3,8 +3,10 @@ using Orchard.AuditTrail.Helpers;
 using Orchard.AuditTrail.Shapes;
 using Orchard.ContentManagement.MetaData.Services;
 using Orchard.DisplayManagement.Implementation;
+using Orchard.Environment.Extensions;
 
 namespace Orchard.AuditTrail.Providers.ContentDefinition.Shapes {
+    [OrchardFeature("Orchard.AuditTrail.ContentDefinition")]
     public class ContentTypePartSettingsUpdatedEventShape : AuditTrailEventShapeAlteration<ContentTypeAuditTrailEventProvider> {
         private readonly ISettingsFormatter _settingsFormatter;
         public ContentTypePartSettingsUpdatedEventShape(ISettingsFormatter settingsFormatter) {
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypeSettingsUpdatedEventShape.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypeSettingsUpdatedEventShape.cs
index 5929e6d8d..07511abad 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypeSettingsUpdatedEventShape.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Providers/ContentDefinition/Shapes/ContentTypeSettingsUpdatedEventShape.cs
@@ -3,8 +3,10 @@ using Orchard.AuditTrail.Helpers;
 using Orchard.AuditTrail.Shapes;
 using Orchard.ContentManagement.MetaData.Services;
 using Orchard.DisplayManagement.Implementation;
+using Orchard.Environment.Extensions;
 
 namespace Orchard.AuditTrail.Providers.ContentDefinition.Shapes {
+    [OrchardFeature("Orchard.AuditTrail.ContentDefinition")]
     public class ContentTypeSettingsUpdatedEventShape : AuditTrailEventShapeAlteration<ContentTypeAuditTrailEventProvider> {
         private readonly ISettingsFormatter _settingsFormatter;
         public ContentTypeSettingsUpdatedEventShape(ISettingsFormatter settingsFormatter) {
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/AuditTrailEventDisplayBuilder.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/AuditTrailEventDisplayBuilder.cs
index 1f71abe3b..6a25cabff 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/AuditTrailEventDisplayBuilder.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/AuditTrailEventDisplayBuilder.cs
@@ -18,7 +18,7 @@ namespace Orchard.AuditTrail.Services {
 
         public dynamic BuildDisplay(AuditTrailEventRecord record, string displayType) {
             var eventData = _serializer.Deserialize(record.EventData);
-            var descriptor = _auditTrailManager.DescribeEvent(record.FullEventName);
+            var descriptor = _auditTrailManager.DescribeEvent(record);
             var auditTrailEventShape = New.AuditTrailEvent(Record: record, EventData: eventData, Descriptor: descriptor);
             var metaData = (ShapeMetadata)auditTrailEventShape.Metadata;
             metaData.DisplayType = displayType;
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/AuditTrailManager.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/AuditTrailManager.cs
index 1c60e7c75..048d50363 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/AuditTrailManager.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/AuditTrailManager.cs
@@ -184,6 +184,10 @@ namespace Orchard.AuditTrail.Services {
             return context;
         }
 
+        public AuditTrailEventDescriptor DescribeEvent(AuditTrailEventRecord record) {
+            return DescribeEvent(record.FullEventName) ?? AuditTrailEventDescriptor.Basic(record);
+        }
+
         public AuditTrailEventDescriptor DescribeEvent<T>(string eventName) where T : IAuditTrailEventProvider {
             var fullyQualifiedEventName = EventNameExtensions.GetFullyQualifiedEventName<T>(eventName);
             return DescribeEvent(fullyQualifiedEventName);
@@ -198,11 +202,7 @@ namespace Orchard.AuditTrail.Services {
                 select e;
             var eventDescriptors = eventDescriptorQuery.ToArray();
 
-            if (!eventDescriptors.Any()) {
-                throw new ArgumentException(String.Format("No event named '{0}' exists.", fullyQualifiedEventName), "fullyQualifiedEventName");
-            }
-
-            return eventDescriptors.First();
+            return eventDescriptors.FirstOrDefault();
         }
 
         public IEnumerable<AuditTrailEventRecord> Trim(TimeSpan retentionPeriod) {
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/IAuditTrailManager.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/IAuditTrailManager.cs
index 47fc2876f..9e06e2da8 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/IAuditTrailManager.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/IAuditTrailManager.cs
@@ -55,6 +55,13 @@ namespace Orchard.AuditTrail.Services {
         /// </summary>
         DescribeContext DescribeProviders();
 
+        /// <summary>
+        /// Describes a single audit trail event.
+        /// </summary>
+        /// <param name="record">The audit trail event record for which to find its descriptor.</param>
+        /// <returns>A single audit trail event descriptor.</returns>
+        AuditTrailEventDescriptor DescribeEvent(AuditTrailEventRecord record);
+
         /// <summary>
         /// Describes a single audit trail event.
         /// </summary>
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/Models/AuditTrailEventDescriptor.cs b/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/Models/AuditTrailEventDescriptor.cs
index 66d8ad697..cdd9115c7 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/Models/AuditTrailEventDescriptor.cs
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Services/Models/AuditTrailEventDescriptor.cs
@@ -1,3 +1,5 @@
+using System.Linq;
+using Orchard.AuditTrail.Models;
 using Orchard.Localization;
 
 namespace Orchard.AuditTrail.Services.Models {
@@ -8,5 +10,21 @@ namespace Orchard.AuditTrail.Services.Models {
         public LocalizedString Description { get; set; }
         public bool IsEnabledByDefault { get; set; }
         public bool IsMandatory { get; set; }
+
+        /// <summary>
+        /// Returns a basic descriptor based on an event record.
+        /// This is useful in cases where event records were previously stored by providers that are no longer enabled.
+        /// </summary>
+        public static AuditTrailEventDescriptor Basic(AuditTrailEventRecord record) {
+            return new AuditTrailEventDescriptor {
+                CategoryDescriptor = new AuditTrailCategoryDescriptor {
+                    Category = record.Category,
+                    Events = Enumerable.Empty<AuditTrailEventDescriptor>(),
+                    Name = new LocalizedString(record.Category)
+                },
+                Event = record.EventName,
+                Name = new LocalizedString(record.EventName)
+            };
+        }
     }
 }
\ No newline at end of file
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-FieldSettingsUpdated.SummaryAdmin.cshtml b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-FieldSettingsUpdated.SummaryAdmin.cshtml
index c4d82b0f8..a9d9eaa8b 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-FieldSettingsUpdated.SummaryAdmin.cshtml
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-FieldSettingsUpdated.SummaryAdmin.cshtml
@@ -9,7 +9,7 @@
     var contentFieldName = eventData.Get<string>("ContentFieldName");
     var oldDisplayName = (string)Model.OldDisplayName;
     var newDisplayName = (string)Model.NewDisplayName;
-    var diff = (DiffDictionary<string, string>)Model.Diff;
+    var diff = (DiffDictionary<string, string>)Model.Diff ?? new DiffDictionary<string, string>();
 }
 <section class="audittrail-contentpart-eventsummary">
     @T("Settings for the field <strong>{0}</strong> attached to the {1} content part were updated:", contentFieldName, Html.ContentPartEditLink(contentPartName))
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-FieldSettingsUpdated.cshtml b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-FieldSettingsUpdated.cshtml
index 1fc630501..21096ce83 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-FieldSettingsUpdated.cshtml
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-FieldSettingsUpdated.cshtml
@@ -9,7 +9,7 @@
     var contentFieldName = eventData.Get<string>("ContentFieldName");
     var oldDisplayName = (string)Model.OldDisplayName;
     var newDisplayName = (string)Model.NewDisplayName;
-    var diff = (DiffDictionary<string, string>)Model.Diff;
+    var diff = (DiffDictionary<string, string>)Model.Diff ?? new DiffDictionary<string, string>();
 }
 <section class="audittrail-contentpart-eventsummary">
     @T("Settings for the field <strong>{0}</strong> attached to the {1} content part were updated:", contentFieldName, Html.ContentPartEditLink(contentPartName))
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.SummaryAdmin.cshtml b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.SummaryAdmin.cshtml
index 3860fdefe..d8dbc4483 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.SummaryAdmin.cshtml
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.SummaryAdmin.cshtml
@@ -6,7 +6,7 @@
 @{
     var eventData = (IDictionary<string, object>)Model.EventData;
     var contentPartName = eventData.Get<string>("ContentPartName");
-    var diff = (DiffDictionary<string, string>)Model.Diff;
+    var diff = (DiffDictionary<string, string>)Model.Diff ?? new DiffDictionary<string, string>();
 }
 <section class="audittrail-contentpart-eventsummary">
     @T("Settings for the content part {0} were changed:", Html.ContentPartEditLink(contentPartName))
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.cshtml b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.cshtml
index a3cceb3eb..fd078d743 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.cshtml
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.cshtml
@@ -6,7 +6,7 @@
 @{
     var eventData = (IDictionary<string, object>)Model.EventData;
     var contentPartName = eventData.Get<string>("ContentPartName");
-    var diff = (DiffDictionary<string, string>)Model.Diff;
+    var diff = (DiffDictionary<string, string>)Model.Diff ?? new DiffDictionary<string, string>();
 }
 <section class="audittrail-contentpart-eventsummary">
     @T("Settings for the content part {0} were changed:", Html.ContentPartEditLink(contentPartName))
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-PartSettingsUpdated.SummaryAdmin.cshtml b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-PartSettingsUpdated.SummaryAdmin.cshtml
index 59e4a9f17..f9093230e 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-PartSettingsUpdated.SummaryAdmin.cshtml
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-PartSettingsUpdated.SummaryAdmin.cshtml
@@ -7,7 +7,7 @@
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
     var contentPartName = eventData.Get<string>("ContentPartName");
-    var diff = (DiffDictionary<string, string>)Model.Diff;
+    var diff = (DiffDictionary<string, string>)Model.Diff ?? new DiffDictionary<string, string>();
 }
 <section class="audittrail-contenttype-eventsummary">
     @T("Settings for the content part {0} attached to the content type {1} were changed:", Html.ContentPartEditLink(contentPartName), Html.ContentTypeEditLink(contentTypeName))
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.SummaryAdmin.cshtml b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.SummaryAdmin.cshtml
index 4ec9f7610..d82183750 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.SummaryAdmin.cshtml
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.SummaryAdmin.cshtml
@@ -6,7 +6,7 @@
 @{
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
-    var diff = (DiffDictionary<string, string>) Model.Diff;
+    var diff = (DiffDictionary<string, string>) Model.Diff ?? new DiffDictionary<string, string>();
 }
 <section class="audittrail-contenttype-eventsummary">
     @T("Settings for the content type {0} were changed:", Html.ContentTypeEditLink(contentTypeName))
diff --git a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.cshtml b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.cshtml
index 603249d2d..6664880b4 100644
--- a/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.cshtml
+++ b/src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.cshtml
@@ -6,7 +6,7 @@
 @{
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
-    var diff = (DiffDictionary<string, string>) Model.Diff;
+    var diff = (DiffDictionary<string, string>) Model.Diff ?? new DiffDictionary<string, string>();
 }
 <section class="audittrail-contenttype-eventsummary">
     @T("Settings for the content type {0} were changed:", Html.ContentTypeEditLink(contentTypeName))