ImportError: numpy.core.multiarray failed to import

How to fix ImportError: numpy.core.multiarray failed to import

Your numpy install is broken, not your code. First check which python and numpy you are actually running, then cleanly reinstall numpy (uninstall, then install, no cache). If you mix conda and pip, reinstall numpy from the same manager that owns the environment. This error means Python found numpy's Python files but its compiled C extension failed to load.

The exact error

ImportError: numpy.core.multiarray failed to import

Fix it

1. Confirm the broken env: run python -c "import sys; print(sys.executable)" and python -m pip show numpy. Expected: both point at the same environment; note the numpy version

2. Clean reinstall: python -m pip uninstall -y numpy then python -m pip install --no-cache-dir numpy. Expected: python -c "import numpy; print(numpy.__version__)" prints a version with no error

3. If you use conda, use conda install -c conda-forge numpy (or force-reinstall) instead of mixing pip into a conda env. Expected: import numpy works and dependent packages (pandas, opencv) import too

When this applies

any import numpy (or import of a package that needs numpy, like cv2) dies with numpy.core.multiarray failed to import

When this does NOT apply

No module named 'numpy' (nothing installed) or a pure-Python cannot import name error

Versions

any numpy, usually after upgrades or mixed pip/conda installs

Why it happens

The compiled multiarray extension does not match the interpreter or is corrupted: partial upgrades, pip-vs-conda mixes, or copying site-packages between Pythons.

Edge cases

If reinstall fails the same way, check for multiple numpy copies on sys.path (IDE virtualenv confusion) or a 32/64-bit mismatch.