diff --git a/docs/Manual_Setup_Guide.md b/docs/Manual_Setup_Guide.md
index d2512e3be..52e344454 100644
--- a/docs/Manual_Setup_Guide.md
+++ b/docs/Manual_Setup_Guide.md
@@ -179,3 +179,16 @@ Before setting up the Python backend and sync-microservice, you need to have **M
     ```
 
     For other systems, consult your distribution's documentation.
+
+  ### ONNX Runtime warning on Windows 11 (safe to ignore)
+
+While running backend tests or starting the PictoPy backend on Windows 11, you may see a warning similar to:
+
+UserWarning: Unsupported Windows version (11).
+ONNX Runtime supports Windows 10 and above.
+
+This warning is **harmless**. If backend tests pass successfully and the application runs as expected, the setup is working correctly.
+
+The warning originates from ONNX Runtime's internal OS version check and does **not** indicate a compatibility issue with PictoPy on Windows 11.
+
+