Initialze Newznab will delete any with a null/empty name or URL.

NzbDrone.Core/Providers/NewznabProvider.cs

@@ -74,6 +74,12 @@ namespace NzbDrone.Core.Providers
             {
                 var currentIndexers = All();
 
+                Logger.Debug("Deleting broken Newznab indexer");
+                var brokenIndexers = currentIndexers.Where(i => String.IsNullOrEmpty(i.Name) || String.IsNullOrWhiteSpace(i.Url)).ToList();
+                brokenIndexers.ForEach(e => _database.Delete<NewznabDefinition>(e.Id));
+
+                currentIndexers = All();
+
                 foreach(var feedProvider in indexers)
                 {
                     try

NzbDrone.Core/Repository/NewznabDefinition.cs

@@ -1,4 +1,5 @@
 using System;
+using System.ComponentModel.DataAnnotations;
 using PetaPoco;
 
 namespace NzbDrone.Core.Repository
@@ -11,8 +12,10 @@ namespace NzbDrone.Core.Repository
 
         public Boolean Enable { get; set; }
 
+        [DisplayFormat(ConvertEmptyStringToNull = false)]
         public String Name { get; set; }
 
+        [DisplayFormat(ConvertEmptyStringToNull = false)]
         public String Url { get; set; }
 
         public String ApiKey { get; set; }