diff --git a/AppScaffolding/AppScaffolding.csproj b/AppScaffolding/AppScaffolding.csproj
index 00706f18..bcfbd257 100644
--- a/AppScaffolding/AppScaffolding.csproj
+++ b/AppScaffolding/AppScaffolding.csproj
@@ -3,7 +3,7 @@
 
   <PropertyGroup>
     <TargetFramework>net6.0</TargetFramework>
-    <Version>6.6.3.1</Version>
+    <Version>6.6.4.1</Version>
   </PropertyGroup>
 
   <ItemGroup>
diff --git a/AudibleUtilities/ApiExtended.cs b/AudibleUtilities/ApiExtended.cs
index 84e29508..3d311457 100644
--- a/AudibleUtilities/ApiExtended.cs
+++ b/AudibleUtilities/ApiExtended.cs
@@ -209,7 +209,8 @@ namespace AudibleUtilities
 						new Series
 						{
 							Asin = parent.Asin,
-							Sequence = parent.Relationships.Single(r => r.Asin == child.Asin).Sort.ToString(),
+							// This should properly be Single() not FirstOrDefault(), but FirstOrDefault is defensive for malformed data from audible
+							Sequence = parent.Relationships.FirstOrDefault(r => r.Asin == child.Asin).Sort.ToString(),
 							Title = parent.TitleWithSubtitle
 						}
 					};
diff --git a/DtoImporterService/BookImporter.cs b/DtoImporterService/BookImporter.cs
index cb2e99f4..2ee45574 100644
--- a/DtoImporterService/BookImporter.cs
+++ b/DtoImporterService/BookImporter.cs
@@ -94,7 +94,8 @@ namespace DtoImporterService
 			// nested logic is required so order of names is retained. else, contributors may appear in the order they were inserted into the db
 			var authors = item
 				.Authors
-				.Select(a => DbContext.Contributors.Local.Single(c => a.Name == c.Name))
+				// This should properly be Single() not FirstOrDefault(), but FirstOrDefault is defensive
+				.Select(a => DbContext.Contributors.Local.FirstOrDefault(c => a.Name == c.Name))
 				.ToList();
 
 			var narrators
@@ -104,7 +105,8 @@ namespace DtoImporterService
 				// nested logic is required so order of names is retained. else, contributors may appear in the order they were inserted into the db
 				: item
 					.Narrators
-					.Select(n => DbContext.Contributors.Local.Single(c => n.Name == c.Name))
+					// This should properly be Single() not FirstOrDefault(), but FirstOrDefault is defensive
+					.Select(n => DbContext.Contributors.Local.FirstOrDefault(c => n.Name == c.Name))
 					.ToList();
 
 			// categories are laid out for a breadcrumb. category is 1st, subcategory is 2nd
@@ -154,7 +156,8 @@ namespace DtoImporterService
 			var publisherName = item.Publisher;
 			if (!string.IsNullOrWhiteSpace(publisherName))
 			{
-				var publisher = DbContext.Contributors.Local.Single(c => publisherName == c.Name);
+				// This should properly be Single() not FirstOrDefault(), but FirstOrDefault is defensive
+				var publisher = DbContext.Contributors.Local.FirstOrDefault(c => publisherName == c.Name);
 				book.ReplacePublisher(publisher);
 			}
 
diff --git a/DtoImporterService/ContributorImporter.cs b/DtoImporterService/ContributorImporter.cs
index 5dce7362..e37a160e 100644
--- a/DtoImporterService/ContributorImporter.cs
+++ b/DtoImporterService/ContributorImporter.cs
@@ -82,7 +82,8 @@ namespace DtoImporterService
 				);
 			foreach (var name in newPeople)
 			{
-				var p = groupby.Single(g => g.Name == name).People.First();
+				// This should properly be Single() not FirstOrDefault(), but FirstOrDefault is defensive
+				var p = groupby.FirstOrDefault(g => g.Name == name).People.First();
 
 				try
 				{
diff --git a/DtoImporterService/LibraryBookImporter.cs b/DtoImporterService/LibraryBookImporter.cs
index d90eda7b..5b5e5aa5 100644
--- a/DtoImporterService/LibraryBookImporter.cs
+++ b/DtoImporterService/LibraryBookImporter.cs
@@ -53,7 +53,8 @@ namespace DtoImporterService
 				var newItem = gb.ImportItems.First();
 
 				var libraryBook = new LibraryBook(
-					DbContext.Books.Local.Single(b => b.AudibleProductId == newItem.DtoItem.ProductId),
+					// This should properly be Single() not FirstOrDefault(), but FirstOrDefault is defensive
+					DbContext.Books.Local.FirstOrDefault(b => b.AudibleProductId == newItem.DtoItem.ProductId),
 					newItem.DtoItem.DateAdded,
 					newItem.AccountId);
 				try