diff --git a/lib/synx/xcodeproj_ext/project/object/abstract_object.rb b/lib/synx/xcodeproj_ext/project/object/abstract_object.rb
index 8e7cdf4..51d8ece 100644
--- a/lib/synx/xcodeproj_ext/project/object/abstract_object.rb
+++ b/lib/synx/xcodeproj_ext/project/object/abstract_object.rb
@@ -12,8 +12,12 @@ module Xcodeproj
         end
 
         def work_pathname
-          # hierarchy path has a leading '/' that will break path concatenation
-          @work_pathname ||= project.work_root_pathname + hierarchy_path[1..-1]
+          @work_pathname ||= if hierarchy_path
+            # hierarchy path has a leading '/' that will break path concatenation
+            project.work_root_pathname + hierarchy_path[1..-1]
+          else
+            project.work_root_pathname
+          end
         end
 
         def ensure_internal_consistency(group)