diff --git a/io_scene_psk_psa/psa/builder.py b/io_scene_psk_psa/psa/builder.py
index 825676a..276d7a9 100644
--- a/io_scene_psk_psa/psa/builder.py
+++ b/io_scene_psk_psa/psa/builder.py
@@ -54,7 +54,7 @@ class PsaBuilder(object):
         # Ensure that the exported hierarchy has a single root bone.
         root_bones = [x for x in bones if x.parent is None]
         if len(root_bones) > 1:
-            root_bone_names = [x.name for x in bones]
+            root_bone_names = [x.name for x in root_bones]
             raise RuntimeError('Exported bone hierarchy must have a single root bone.'
                                f'The bone hierarchy marked for export has {len(root_bones)} root bones: {root_bone_names}')
 
diff --git a/io_scene_psk_psa/psk/builder.py b/io_scene_psk_psa/psk/builder.py
index c715f39..44425cc 100644
--- a/io_scene_psk_psa/psk/builder.py
+++ b/io_scene_psk_psa/psk/builder.py
@@ -91,7 +91,7 @@ class PskBuilder(object):
             print('root bones')
             print(root_bones)
             if len(root_bones) > 1:
-                root_bone_names = [x.name for x in bones]
+                root_bone_names = [x.name for x in root_bones]
                 raise RuntimeError('Exported bone hierarchy must have a single root bone.'
                                    f'The bone hierarchy marked for export has {len(root_bones)} root bones: {root_bone_names}')