diff --git a/src/gutenapp/gutenapp/AssemblyFileResolver.cs b/src/gutenapp/gutenapp/AssemblyFileResolver.cs
index e3db2c7..92226fe 100644
--- a/src/gutenapp/gutenapp/AssemblyFileResolver.cs
+++ b/src/gutenapp/gutenapp/AssemblyFileResolver.cs
@@ -205,7 +205,10 @@ public class AssemblyFileResolver
             foreach (var dir in dirs)
             {
                 var (libraryFound, libraryPath) = ProbeDirectoryForLibrary(dir, library);
-                candidateLibs.Add(libraryPath);
+                if (libraryFound)
+                {
+                    candidateLibs.Add(libraryPath);
+                }
             }
         }
 
diff --git a/src/gutenapp/gutenapp/Program.cs b/src/gutenapp/gutenapp/Program.cs
index e66da97..d7d6193 100644
--- a/src/gutenapp/gutenapp/Program.cs
+++ b/src/gutenapp/gutenapp/Program.cs
@@ -30,7 +30,7 @@ static async Task Main(string[] args)
 
             if (!wordcountFound || !mostcommonwordsFound)
             {
-                throw new Exception();
+                throw new ApplicationException("Can't find 'wordcount' or 'mostcommonwords' components.");
             }
 
             var (wordcountContext, wordCountAsm) = ComponentContext.CreateContext(wordCountPath);