diff --git a/src/NzbDrone.Core/Indexers/Newznab/NewznabSettings.cs b/src/NzbDrone.Core/Indexers/Newznab/NewznabSettings.cs
index b8b5ec7a1..0e3121e98 100644
--- a/src/NzbDrone.Core/Indexers/Newznab/NewznabSettings.cs
+++ b/src/NzbDrone.Core/Indexers/Newznab/NewznabSettings.cs
@@ -70,7 +70,7 @@ namespace NzbDrone.Core.Indexers.Newznab
         [FieldDefinition(2, Label = "API Key", Privacy = PrivacyLevel.ApiKey)]
         public string ApiKey { get; set; }
 
-        [FieldDefinition(3, Label = "Categories", Type = FieldType.Select, SelectOptionsProviderAction = "newznabCategories", HelpText = "Drop down list, leave blank to disable all categories")]
+        [FieldDefinition(3, Label = "Categories", Type = FieldType.Select, SelectOptionsProviderAction = "newznabCategories", HelpText = "Drop down list; at least one category must be selected.")]
         public IEnumerable<int> Categories { get; set; }
 
         [FieldDefinition(4, Type = FieldType.Number, Label = "Early Download Limit", HelpText = "Time before release date Lidarr will download from this indexer, empty is no limit", Unit = "days", Advanced = true)]