diff --git a/io_anim_bvh/export_bvh.py b/io_anim_bvh/export_bvh.py
index 6ee688be6a59befdc934f7b228621a200598bd95..c6173b6a01080b8527460084d57d6111244fa08f 100644
--- a/io_anim_bvh/export_bvh.py
+++ b/io_anim_bvh/export_bvh.py
@@ -141,21 +141,21 @@ def write_armature(context,
     # so we can write motion
 
     class DecoratedBone(object):
-        __slots__ = (\
-        "name",  # bone name, used as key in many places
-        "parent",  # decorated bone parent, set in a later loop
-        "rest_bone",  # blender armature bone
-        "pose_bone",  # blender pose bone
-        "pose_mat",  # blender pose matrix
-        "rest_arm_mat",  # blender rest matrix (armature space)
-        "rest_local_mat",  # blender rest batrix (local space)
-        "pose_imat",  # pose_mat inverted
-        "rest_arm_imat",  # rest_arm_mat inverted
-        "rest_local_imat",  # rest_local_mat inverted
-        "prev_euler",  # last used euler to preserve euler compability in between keyframes
-        "connected",  # is the bone connected to the parent bone?
-        "rot_order",
-        "rot_order_str",
+        __slots__ = (
+            "name",  # bone name, used as key in many places
+            "parent",  # decorated bone parent, set in a later loop
+            "rest_bone",  # blender armature bone
+            "pose_bone",  # blender pose bone
+            "pose_mat",  # blender pose matrix
+            "rest_arm_mat",  # blender rest matrix (armature space)
+            "rest_local_mat",  # blender rest batrix (local space)
+            "pose_imat",  # pose_mat inverted
+            "rest_arm_imat",  # rest_arm_mat inverted
+            "rest_local_imat",  # rest_local_mat inverted
+            "prev_euler",  # last used euler to preserve euler compability in between keyframes
+            "connected",  # is the bone connected to the parent bone?
+            "rot_order",
+            "rot_order_str",
         )
 
         _eul_order_lookup = {
diff --git a/io_scene_3ds/__init__.py b/io_scene_3ds/__init__.py
index e7934afc885071eaf7aebbb28bc8608970ccb8b7..2206c20ddf654ffff7aa29fbd76edc3f509ce445 100644
--- a/io_scene_3ds/__init__.py
+++ b/io_scene_3ds/__init__.py
@@ -43,7 +43,12 @@ if "bpy" in locals():
 
 import bpy
 from bpy.props import StringProperty, FloatProperty, BoolProperty, EnumProperty
-from bpy_extras.io_utils import ImportHelper, ExportHelper, axis_conversion
+
+from bpy_extras.io_utils import (ImportHelper,
+                                 ExportHelper,
+                                 axis_conversion,
+                                 axis_conversion_ensure,
+                                 )
 
 
 class Import3DS(bpy.types.Operator, ImportHelper):
@@ -82,6 +87,9 @@ class Import3DS(bpy.types.Operator, ImportHelper):
             default='Z',
             )
 
+    def check(self, context):
+        return axis_conversion_ensure(self, "axis_forward", "axis_up")
+
     def execute(self, context):
         from . import import_3ds
 
@@ -127,6 +135,9 @@ class Export3DS(bpy.types.Operator, ExportHelper):
             default='Z',
             )
 
+    def check(self, context):
+        return axis_conversion_ensure(self, "axis_forward", "axis_up")
+
     def execute(self, context):
         from . import export_3ds
 
diff --git a/io_scene_fbx/__init__.py b/io_scene_fbx/__init__.py
index a805f713410fa46b4cf9592a60d1420d49267085..d17e2dd560d5a084538944ad2251d9bda86c7626 100644
--- a/io_scene_fbx/__init__.py
+++ b/io_scene_fbx/__init__.py
@@ -41,7 +41,12 @@ if "bpy" in locals():
 
 import bpy
 from bpy.props import StringProperty, BoolProperty, FloatProperty, EnumProperty
-from bpy_extras.io_utils import ExportHelper, path_reference_mode, axis_conversion
+
+from bpy_extras.io_utils import (ExportHelper, 
+                                 path_reference_mode,
+                                 axis_conversion,
+                                 axis_conversion_ensure,
+                                 )
 
 
 class ExportFBX(bpy.types.Operator, ExportHelper):
@@ -132,6 +137,9 @@ class ExportFBX(bpy.types.Operator, ExportHelper):
     def check_extension(self):
         return self.batch_mode == 'OFF'
 
+    def check(self, context):
+        return axis_conversion_ensure(self, "axis_forward", "axis_up")
+
     def execute(self, context):
         from mathutils import Matrix
         if not self.filepath:
diff --git a/io_scene_map/__init__.py b/io_scene_map/__init__.py
index d329599881fd9c2c736220ff690d4dc62a89bbee..a9610ef5c2180f9374181e27f66bc26a1f762a56 100644
--- a/io_scene_map/__init__.py
+++ b/io_scene_map/__init__.py
@@ -53,6 +53,11 @@ class ExportMAP(bpy.types.Operator, ExportHelper):
     filename_ext = ".map"
     filter_glob = StringProperty(default="*.map", options={'HIDDEN'})
 
+    '''
+    def check(self, context):
+        return axis_conversion_ensure(self, "axis_forward", "axis_up")
+    '''
+
     def execute(self, context):
         # import math
         # from mathutils import Matrix
diff --git a/io_scene_obj/__init__.py b/io_scene_obj/__init__.py
index 694c618daefa2df4b89542234253895d84f77c73..cd8a855d6d22ac54a868a138c26e0957d79cacdb 100644
--- a/io_scene_obj/__init__.py
+++ b/io_scene_obj/__init__.py
@@ -43,7 +43,13 @@ if "bpy" in locals():
 
 import bpy
 from bpy.props import BoolProperty, FloatProperty, StringProperty, EnumProperty
-from bpy_extras.io_utils import ExportHelper, ImportHelper, path_reference_mode, axis_conversion
+
+from bpy_extras.io_utils import (ExportHelper,
+                                 ImportHelper,
+                                 path_reference_mode,
+                                 axis_conversion,
+                                 axis_conversion_ensure,
+                                 )
 
 
 class ImportOBJ(bpy.types.Operator, ImportHelper):
@@ -101,6 +107,9 @@ class ImportOBJ(bpy.types.Operator, ImportHelper):
     # fake prop, only disables split.
     # keep_vertex_order = BoolProperty(name="Keep Vert Order", description="Keep vert and face order, disables split options, enable for morph targets", default= True)
 
+    def check(self, context):
+        return axis_conversion_ensure(self, "axis_forward", "axis_up")
+
     def execute(self, context):
         # print("Selected: " + context.active_object.name)
         from . import import_obj
@@ -213,6 +222,9 @@ class ExportOBJ(bpy.types.Operator, ExportHelper):
 
     path_mode = path_reference_mode
 
+    def check(self, context):
+        return axis_conversion_ensure(self, "axis_forward", "axis_up")
+
     def execute(self, context):
         from . import export_obj
 
diff --git a/io_scene_x3d/__init__.py b/io_scene_x3d/__init__.py
index c49a86a882f049102e38b3e1a9124cf709bdcd39..1d0841e00e1cfbcb16a8ee3c35319271605bc491 100644
--- a/io_scene_x3d/__init__.py
+++ b/io_scene_x3d/__init__.py
@@ -41,7 +41,12 @@ if "bpy" in locals():
 
 import bpy
 from bpy.props import StringProperty, BoolProperty, EnumProperty
-from bpy_extras.io_utils import ImportHelper, ExportHelper, axis_conversion, path_reference_mode
+from bpy_extras.io_utils import (ImportHelper,
+                                 ExportHelper,
+                                 axis_conversion,
+                                 axis_conversion_ensure,
+                                 path_reference_mode,
+                                 )
 
 
 class ImportX3D(bpy.types.Operator, ImportHelper):
@@ -76,6 +81,9 @@ class ImportX3D(bpy.types.Operator, ImportHelper):
             default='Y',
             )
 
+    def check(self, context):
+        return axis_conversion_ensure(self, "axis_forward", "axis_up")
+
     def execute(self, context):
         from . import import_x3d
 
@@ -128,6 +136,9 @@ class ExportX3D(bpy.types.Operator, ExportHelper):
 
     path_mode = path_reference_mode
 
+    def check(self, context):
+        return axis_conversion_ensure(self, "axis_forward", "axis_up")
+
     def execute(self, context):
         from . import export_x3d