Adds some more detailed logging.

src/Umbraco.Core/CoreBootManager.cs

@@ -97,7 +97,18 @@ namespace Umbraco.Core
 
             //now we need to call the initialize methods
             ApplicationEventsResolver.Current.ApplicationEventHandlers
-                .ForEach(x => x.OnApplicationInitialized(UmbracoApplication, ApplicationContext));
+                .ForEach(x =>
+                {
+                    try
+                    {
+                        x.OnApplicationInitialized(UmbracoApplication, ApplicationContext);
+                    }
+                    catch (Exception ex)
+                    {
+                        LogHelper.Error<CoreBootManager>("An error occurred running OnApplicationInitialized for handler " + x.GetType(), ex);
+                        throw;
+                    }
+                });
 
 			_isInitialized = true;
 
@@ -203,7 +214,18 @@ namespace Umbraco.Core
 
             //call OnApplicationStarting of each application events handler
             ApplicationEventsResolver.Current.ApplicationEventHandlers
-                .ForEach(x => x.OnApplicationStarting(UmbracoApplication, ApplicationContext));
+                .ForEach(x =>
+                {
+                    try
+                    {
+                        x.OnApplicationStarting(UmbracoApplication, ApplicationContext);
+                    }
+                    catch (Exception ex)
+                    {
+                        LogHelper.Error<CoreBootManager>("An error occurred running OnApplicationStarting for handler " + x.GetType(), ex);
+                        throw;
+                    }
+                });
 
             if (afterStartup != null)
             {
@@ -229,7 +251,18 @@ namespace Umbraco.Core
             
             //call OnApplicationStarting of each application events handler
             ApplicationEventsResolver.Current.ApplicationEventHandlers
-                .ForEach(x => x.OnApplicationStarted(UmbracoApplication, ApplicationContext));
+                .ForEach(x =>
+                {
+                    try
+                    {
+                        x.OnApplicationStarted(UmbracoApplication, ApplicationContext);
+                    }
+                    catch (Exception ex)
+                    {
+                        LogHelper.Error<CoreBootManager>("An error occurred running OnApplicationStarted for handler " + x.GetType(), ex);
+                        throw;
+                    }
+                });
 
             //Now, startup all of our legacy startup handler
             ApplicationEventsResolver.Current.InstantiateLegacyStartupHandlers();

src/Umbraco.Core/PluginManager.cs

@@ -606,14 +606,10 @@ namespace Umbraco.Core
         /// <returns></returns>
         internal IEnumerable<T> CreateInstances<T>(IEnumerable<Type> types, bool throwException = false)
         {
-            //Have removed logging because it doesn't really need to be logged since the time taken is generally 0ms.
-            //we want to know if it fails ever, not how long it took if it is only 0.
-
             var typesAsArray = types.ToArray();
-            //using (DisposableTimer.DebugDuration<PluginManager>(
-            //	String.Format("Starting instantiation of {0} objects of type {1}", typesAsArray.Length, typeof(T).FullName),
-            //	String.Format("Completed instantiation of {0} objects of type {1}", typesAsArray.Length, typeof(T).FullName)))
-            //{
+
+            LogHelper.Debug<PluginManager>(string.Format("Instantiating {0} objects of type {1}", typesAsArray.Length, typeof (T).FullName));
+            
             var instances = new List<T>();
             foreach (var t in typesAsArray)
             {
@@ -634,7 +630,7 @@ namespace Umbraco.Core
                 }
             }
             return instances;
-            //}
+            
         }
 
         /// <summary>

src/Umbraco.Core/UmbracoApplicationBase.cs

@@ -73,7 +73,18 @@ namespace Umbraco.Core
         protected virtual void OnApplicationStarting(object sender, EventArgs e)
         {
             if (ApplicationStarting != null)
-                ApplicationStarting(sender, e);
+            {
+                try
+                {
+                    ApplicationStarting(sender, e);
+                }
+                catch (Exception ex)
+                {
+                    LogHelper.Error<UmbracoApplicationBase>("An error occurred in an ApplicationStarting event handler", ex);
+                    throw;
+                }
+            }
+                
         }
 
         /// <summary>
@@ -84,7 +95,17 @@ namespace Umbraco.Core
         protected virtual void OnApplicationStarted(object sender, EventArgs e)
         {
             if (ApplicationStarted != null)
-                ApplicationStarted(sender, e);
+            {
+                try
+                {
+                    ApplicationStarted(sender, e);
+                }
+                catch (Exception ex)
+                {
+                    LogHelper.Error<UmbracoApplicationBase>("An error occurred in an ApplicationStarted event handler", ex);
+                    throw;
+                }
+            }
         }
 
         /// <summary>
@@ -95,7 +116,17 @@ namespace Umbraco.Core
         private void OnApplicationInit(object sender, EventArgs e)
         {
             if (ApplicationInit != null)
-                ApplicationInit(sender, e);
+            {
+                try
+                {
+                    ApplicationInit(sender, e);
+                }
+                catch (Exception ex)
+                {
+                    LogHelper.Error<UmbracoApplicationBase>("An error occurred in an ApplicationInit event handler", ex);
+                    throw;
+                }
+            }
         }
 
         /// <summary>