Unreal hangs on Initializing Python on startup

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Fixing UE Hanging on Installing Python Dependencies

Unreal Engine’s Python plugin actually just calls the built-in pip. You can configure pip to use a faster or custom package index if downloads are too slow.

Steps:

  1. Locate the UE-shipped Python interpreter, usually under:

    [UE installation directory]\Engine\Binaries\ThirdParty\Python3\Win64

    You should see a python.exe there.

  2. Open a command prompt in that folder (or cd into it manually).

  3. Set a global pip index URL. For example, the default PyPI:

    python.exe -m pip config set global.index-url https://pypi.org/simple

    Or, if you want to use an alternative CDN mirror (sometimes faster globally):

    python.exe -m pip config set global.index-url https://pypi.org/simple --trusted-host pypi.org

    (You can replace the URL with any mirror you trust.)

  4. Restart Unreal Engine and it should fetch dependencies using the new pip source.

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