Question: I am trying to import imblearn into my python notebook after installing the required modules. However, I am getting the following error:  Additional info: I am using a virtual environment in Visual Studio Code. I've made sure that venv was selected as interpreter and as the notebook kernel. I've reloaded the window and restarted the kernel several times. I have also uninstalled and installed imbalanced-learn and scikit-learn several times, with and without "--upgrade". I'm still getting the same error.  Edit: Full traceback of error { "name": "ImportError", "message": "cannot import name '_MissingValues' from 'sklearn.utils._param_validation' (c:\\Users\\wen\\OneDrive\\Desktop\\Colab_Notebooks\\.venv\\Lib\\site-packages\\sklearn\\utils\\_param_validation.py)", "stack": "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m\n\u001b[1;31mImportError\u001b[0m Traceback (most recent call last)\nCell \u001b[1;32mIn[1], line 1\u001b[0m\n\u001b[1;32m----> 1\u001b[0m \u001b[39mimport\u001b[39;00m \u001b[39mimblearn\u001b[39;00m\n\u001b[0;32m 2\u001b[0m \u001b[39m# Data Processing\u001b[39;00m\n\u001b[0;32m 3\u001b[0m \u001b[39mimport\u001b[39;00m \u001b[39mpandas\u001b[39;00m \u001b[39mas\u001b[39;00m \u001b[39mpd\u001b[39;00m\n\nFile \u001b[1;32mc:\\Users\\wen\\OneDrive\\Desktop\\Colab_Notebooks\\.venv\\Lib\\site-packages\\imblearn\\__init__.py:52\u001b[0m\n\u001b[0;32m 48\u001b[0m sys\u001b[39m.\u001b[39mstderr\u001b[39m.\u001b[39mwrite(\u001b[39m\"\u001b[39m\u001b[39mPartial import of imblearn during the build process.\u001b[39m\u001b[39m\\n\u001b[39;00m\u001b[39m\"\u001b[39m)\n\u001b[0;32m 49\u001b[0m \u001b[39m# We are not importing the rest of scikit-learn during the build\u001b[39;00m\n\u001b[0;32m 50\u001b[0m \u001b[39m# process, as it may not be compiled yet\u001b[39;00m\n\u001b[0;32m 51\u001b[0m \u001b[39melse\u001b[39;00m:\n\u001b[1;32m---> 52\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m \u001b[39mimport\u001b[39;00m (\n\u001b[0;32m 53\u001b[0m combine,\n\u001b[0;32m 54\u001b[0m ensemble,\n\u001b[0;32m 55\u001b[0m exceptions,\n\u001b[0;32m 56\u001b[0m metrics,\n\u001b[0;32m 57\u001b[0m over_sampling,\n\u001b[0;32m 58\u001b[0m pipeline,\n\u001b[0;32m 59\u001b[0m tensorflow,\n\u001b[0;32m 60\u001b[0m under_sampling,\n\u001b[0;32m 61\u001b[0m utils,\n\u001b[0;32m 62\u001b[0m )\n\u001b[0;32m 63\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39m_version\u001b[39;00m \u001b[39mimport\u001b[39;00m __version__\n\u001b[0;32m 64\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39mbase\u001b[39;00m \u001b[39mimport\u001b[39;00m FunctionSampler\n\nFile \u001b[1;32mc:\\Users\\wen\\OneDrive\\Desktop\\Colab_Notebooks\\.venv\\Lib\\site-packages\\imblearn\\combine\\__init__.py:5\u001b[0m\n\u001b[0;32m 1\u001b[0m \u001b[39m\"\"\"The :mod:`imblearn.combine` provides methods which combine\u001b[39;00m\n\u001b[0;32m 2\u001b[0m \u001b[39mover-sampling and under-sampling.\u001b[39;00m\n\u001b[0;32m 3\u001b[0m \u001b[39m\"\"\"\u001b[39;00m\n\u001b[1;32m----> 5\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39m_smote_enn\u001b[39;00m \u001b[39mimport\u001b[39;00m SMOTEENN\n\u001b[0;32m 6\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39m_smote_tomek\u001b[39;00m \u001b[39mimport\u001b[39;00m SMOTETomek\n\u001b[0;32m 8\u001b[0m __all__ \u001b[39m=\u001b[39m [\u001b[39m\"\u001b[39m\u001b[39mSMOTEENN\u001b[39m\u001b[39m\"\u001b[39m, \u001b[39m\"\u001b[39m\u001b[39mSMOTETomek\u001b[39m\u001b[39m\"\u001b[39m]\n\nFile \u001b[1;32mc:\\Users\\wen\\OneDrive\\Desktop\\Colab_Notebooks\\.venv\\Lib\\site-packages\\imblearn\\combine\\_smote_enn.py:12\u001b[0m\n\u001b[0;32m 9\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39msklearn\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mbase\u001b[39;00m \u001b[39mimport\u001b[39;00m clone\n\u001b[0;32m 10\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39msklearn\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mutils\u001b[39;00m \u001b[39mimport\u001b[39;00m check_X_y\n\u001b[1;32m---> 12\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mbase\u001b[39;00m \u001b[39mimport\u001b[39;00m BaseSampler\n\u001b[0;32m 13\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mover_sampling\u001b[39;00m \u001b[39mimport\u001b[39;00m SMOTE\n\u001b[0;32m 14\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mover_sampling\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mbase\u001b[39;00m \u001b[39mimport\u001b[39;00m BaseOverSampler\n\nFile \u001b[1;32mc:\\Users\\wen\\OneDrive\\Desktop\\Colab_Notebooks\\.venv\\Lib\\site-packages\\imblearn\\base.py:21\u001b[0m\n\u001b[0;32m 18\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39msklearn\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mutils\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mmulticlass\u001b[39;00m \u001b[39mimport\u001b[39;00m check_classification_targets\n\u001b[0;32m 20\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39mutils\u001b[39;00m \u001b[39mimport\u001b[39;00m check_sampling_strategy, check_target_type\n\u001b[1;32m---> 21\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39mutils\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39m_param_validation\u001b[39;00m \u001b[39mimport\u001b[39;00m validate_parameter_constraints\n\u001b[0;32m 22\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39m.\u001b[39;00m\u001b[39mutils\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39m_validation\u001b[39;00m \u001b[39mimport\u001b[39;00m ArraysTransformer\n\u001b[0;32m 25\u001b[0m \u001b[39mclass\u001b[39;00m \u001b[39mSamplerMixin\u001b[39;00m(BaseEstimator, metaclass\u001b[39m=\u001b[39mABCMeta):\n\nFile \u001b[1;32mc:\\Users\\wen\\OneDrive\\Desktop\\Colab_Notebooks\\.venv\\Lib\\site-packages\\imblearn\\utils\\_param_validation.py:908\u001b[0m\n\u001b[0;32m 906\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39msklearn\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mutils\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39m_param_validation\u001b[39;00m \u001b[39mimport\u001b[39;00m generate_valid_param \u001b[39m# noqa\u001b[39;00m\n\u001b[0;32m 907\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39msklearn\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mutils\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39m_param_validation\u001b[39;00m \u001b[39mimport\u001b[39;00m validate_parameter_constraints \u001b[39m# noqa\u001b[39;00m\n\u001b[1;32m--> 908\u001b[0m \u001b[39mfrom\u001b[39;00m \u001b[39msklearn\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39mutils\u001b[39;00m\u001b[39m.\u001b[39;00m\u001b[39m_param_validation\u001b[39;00m \u001b[39mimport\u001b[39;00m (\n\u001b[0;32m 909\u001b[0m HasMethods,\n\u001b[0;32m 910\u001b[0m Hidden,\n\u001b[0;32m 911\u001b[0m Interval,\n\u001b[0;32m 912\u001b[0m Options,\n\u001b[0;32m 913\u001b[0m StrOptions,\n\u001b[0;32m 914\u001b[0m _ArrayLikes,\n\u001b[0;32m 915\u001b[0m _Booleans,\n\u001b[0;32m 916\u001b[0m _Callables,\n\u001b[0;32m 917\u001b[0m _CVObjects,\n\u001b[0;32m 918\u001b[0m _InstancesOf,\n\u001b[0;32m 919\u001b[0m _IterablesNotString,\n\u001b[0;32m 920\u001b[0m _MissingValues,\n\u001b[0;32m 921\u001b[0m _NoneConstraint,\n\u001b[0;32m 922\u001b[0m _PandasNAConstraint,\n\u001b[0;32m 923\u001b[0m _RandomStates,\n\u001b[0;32m 924\u001b[0m _SparseMatrices,\n\u001b[0;32m 925\u001b[0m _VerboseHelper,\n\u001b[0;32m 926\u001b[0m make_constraint,\n\u001b[0;32m 927\u001b[0m validate_params,\n\u001b[0;32m 928\u001b[0m )\n\n\u001b[1;31mImportError\u001b[0m: cannot import name '_MissingValues' from 'sklearn.utils._param_validation' (c:\\Users\\wen\\OneDrive\\Desktop\\Colab_Notebooks\\.venv\\Lib\\site-packages\\sklearn\\utils\\_param_validation.py)" }   The versions of the modules are as follows: scikit-learn 1.3.0 imblearn 0.0 imbalanced-learn 0.10.1

Answer: I was having the same issue, downgrading to scikit-learn 1.2.2 fixed it for me