diff --git a/registry.py b/registry.py
index 70734cc..b0db828 100644
--- a/registry.py
+++ b/registry.py
@@ -7,7 +7,8 @@ _timer_registry: list[Callable[..., int | None]] = []
 
 # BPY CLASSES
 def register_class(cls: type) -> type:
-    _bpy_class_registry.append(cls)
+    if cls not in _bpy_class_registry:
+        _bpy_class_registry.append(cls)
     return cls
 
 def get() -> list[type]:
@@ -26,12 +27,22 @@ def get_class_by_name(name: str) -> type | None:
     return None
 
 def blender_register_classes():
-    for module in get():
-        bpy.utils.register_class(module)
+    for cls in _bpy_class_registry:
+        try:
+            bpy.utils.register_class(cls)
+        except Exception as e:
+            print(f"Nodeslicer: Failed to register {cls}: {e}")
 
 def blender_unregister_classes():
-    for module in get():
-        bpy.utils.unregister_class(module)
+    for cls in reversed(_bpy_class_registry):
+        try:
+            if hasattr(cls, "is_registered") and cls.is_registered: # type: ignore
+                 bpy.utils.unregister_class(cls)
+            elif hasattr(cls, "bl_rna"):
+                 # Fallback for classes that don't have is_registered (older Blender or certain types)
+                 bpy.utils.unregister_class(cls)
+        except Exception as e:
+            print(f"Nodeslicer: Failed to unregister {cls}: {e}")
 
 # TIMERS
 def register_timer(clb: Callable[..., Any]):