System.InvalidOperationException thrown on the CD if the Core database is disabled


A default installation of a Content Delivery (CD) instance uses only a Web database. However, some site definitions might refer to the Core database:
<site name="shell" .....database="core" ....
<site name="login" .... database="core"....
<site name="modules_shell" ..... database="core"
The following error message can be found in the CD log records:
ERROR Exception while handling event Sitecore.Data.Eventing.Remote.SavedItemRemoteEvent
Exception: System.InvalidOperationException
Message: Could not find configuration node: databases/database[@id='core']
Source: Sitecore.Kernel
   at Sitecore.Configuration.DefaultFactory.GetConfigNode(String xpath, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.CreateObject(String configPath, String[] parameters, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.GetDatabase(String name, Boolean assert)
   at Sitecore.Configuration.DefaultFactory.GetDatabase(String name)
   at Sitecore.Caching.ItemCache.FindAvailableKeys(SiteInfo site, ID itemId)
   at Sitecore.Caching.ItemCache.RemoveItemFromFilterCaches(ID itemId)
   at Sitecore.Caching.ItemCache.RemoveItem(ID itemId)
   at System.EventHandler`1.Invoke(Object sender, TEventArgs e)
   at Sitecore.Eventing.Subscription`1.Invoke(Object instance, EventContext context)
   at Sitecore.Eventing.EventProvider.RaiseEvent(Object event, Type eventType, EventContext context


To resolve the issue, you can comment out the shell, login, and modules_shell site nodes, as shown in the following example: