Hello Rasa Community and Support Team, I am encountering a persistent and blocking OSError: [WinError 123] when trying to run a trained model on Windows using Rasa Pro. The training process completes successfully, but I cannot interact with the model using rasa shell or rasa run. I have followed a very detailed troubleshooting process and believe this may be a bug in how model archives are handled on Windows in this version. Environment Details **Rasa Pro Version : 3.12.17 **Minimum Compatible Version: 3.11.0rc1 **Rasa SDK Version : 3.12.0 **Python Version : 3.10.18 **Operating System : Windows-10-10.0.26100-SP0 Installation Method: uv pip install rasa-pro. Problem Description rasa train runs and completes successfully, creating a model in the models/ directory. rasa run actions starts the action server successfully, registering all custom actions. When I run rasa shell, it immediately fails while trying to load the model. Error Log from rasa shell: <a name="p-168308-error-rasa__main__-error-oserror-winerror-123-the-filename-directory-name-or-volume-label-syntax-is-incorrect-cusersv4varappdatalocaltemptmphn0ukstrcomponentstrain_tedpolicy1-event_keycliexceptiongeneral_exception-3" class="anchor" href="#p-168308-error-rasa__main__-error-oserror-winerror-123-the-filename-directory-name-or-volume-label-syntax-is-incorrect-cusersv4varappdatalocaltemptmphn0ukstrcomponentstrain_tedpolicy1-event_keycliexceptiongeneral_exception-3" aria-label="Heading link"> ERROR rasa.main - [error] OSError: [WinError 123] The filename, directory name, or volume label syntax is incorrect: ‘\\?\C:\Users\v4var\AppData\Local\Temp\tmphn0ukstr\components/train_TEDPolicy1’ event_key=cli.exception.general_exception … (full traceback) …` The key error is OSError: [WinError 123] which seems to be caused by an invalid file path mixing Windows (\) and Unix (/) separators during the model extraction process into a temporary directory. Troubleshooting Steps Already Taken Based on extensive debugging, we have tried the following workarounds without success: Created a Clean Environment: The current rasa-pro-env was created from scratch with conda create --name rasa-pro-env python=3.10 to ensure a compatible Python version. Confirmed rasa-pro Installation: uv pip install rasa-pro was run successfully in the new environment. Manual Model Unpacking: To bypass the faulty extraction logic, we manually unpacked the .tar.gz model into a folder named unpacked_model. Verified Unpacked Structure: We confirmed the unpacked_model folder correctly contains the Rasa 3.x model structure: a components/ folder and a metadata.json file. Attempted to Load Unpacked Model: We then tried to run the server by pointing directly to this unpacked directory using rasa run --model unpacked_model. Final Error: This command still fails, but with a different error: No model found.. This happens even after verifying the directory contents and structure are correct with ls unpacked_model immediately before running the command. Using an absolute path in the --model flag also results in No model found. Core Question Given that rasa train works, but loading the model fails with a file path error (WinError 123) and the standard workaround (--model <directory>) also fails (No model found), this seems to be a blocking bug for local development on Windows. Is this a known issue? What is the recommended procedure to load and interact with a trained Rasa Pro model l…

[Rasa Pro Bug] Persistent OSError: [WinError 123] on Windows During Model Loading

hamidsadeghi68 (Hamid Sadeghi) August 10, 2025, 3:51am 4

Hi @m_ashurkina I have the same error with RASA open source:

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