diff --git a/lib/jsduck/app.rb b/lib/jsduck/app.rb
index df848c9ad2790b9ca97b51017fb80ae5e9e8b2b1..abbbe38402e9b1d86f9c98df96bcd14b01e6e0f0 100644
--- a/lib/jsduck/app.rb
+++ b/lib/jsduck/app.rb
@@ -73,7 +73,6 @@ module JsDuck
       @categories = Categories.new(get_doc_formatter, @relations)
       if @opts.categories_path
         @categories.parse(@opts.categories_path)
-        @categories.validate
       else
         @categories.auto_generate
       end
diff --git a/lib/jsduck/categories.rb b/lib/jsduck/categories.rb
index ee35621be07be7ac5436bcedabbc0952f2596b54..61d48347c0aa2ac11f2287332eaeba7468e651ff 100644
--- a/lib/jsduck/categories.rb
+++ b/lib/jsduck/categories.rb
@@ -35,6 +35,8 @@ module JsDuck
           end.flatten
         end
       end
+
+      validate
     end
 
     # Expands class name like 'Foo.*' into multiple class names.