diff --git a/InvenTree/part/models.py b/InvenTree/part/models.py
index 8383431caa..385bae7bf4 100644
--- a/InvenTree/part/models.py
+++ b/InvenTree/part/models.py
@@ -858,13 +858,19 @@ class BomItem(models.Model):
         """
 
         # A part cannot refer to itself in its BOM
-        if self.part == self.sub_part:
-            raise ValidationError({'sub_part': _('Part cannot be added to its own Bill of Materials')})
-
-        # Test for simple recursion
-        for item in self.sub_part.bom_items.all():
-            if self.part == item.sub_part:
-                raise ValidationError({'sub_part': _("Part '{p1}' is  used in BOM for '{p2}' (recursive)".format(p1=str(self.part), p2=str(self.sub_part)))})
+        try:
+            if self.sub_part is not None and self.part is not None:
+                if self.part == self.sub_part:
+                    raise ValidationError({'sub_part': _('Part cannot be added to its own Bill of Materials')})
+        
+            # Test for simple recursion
+            for item in self.sub_part.bom_items.all():
+                if self.part == item.sub_part:
+                    raise ValidationError({'sub_part': _("Part '{p1}' is  used in BOM for '{p2}' (recursive)".format(p1=str(self.part), p2=str(self.sub_part)))})
+        
+        except Part.DoesNotExist:
+            # A blank Part will be caught elsewhere
+            pass
 
     class Meta:
         verbose_name = "BOM Item"