diff --git a/NuKeeper.Abstractions/NuGet/NuGetSources.cs b/NuKeeper.Abstractions/NuGet/NuGetSources.cs
index b3bab8f05..3f61d2fe1 100644
--- a/NuKeeper.Abstractions/NuGet/NuGetSources.cs
+++ b/NuKeeper.Abstractions/NuGet/NuGetSources.cs
@@ -32,7 +32,7 @@ public NuGetSources(IEnumerable<PackageSource> sources)
 
             if (!items.Any())
             {
-                throw new ArgumentException(nameof(items));
+                throw new ArgumentException("No package sources defined", nameof(sources));
             }
 
             Items = items;