TL;DR: pyarrow's bundled native library will not load on your Windows box. Reinstall pyarrow from a fresh wheel and make sure the Visual C++ redistributable is installed.

## The error
```text
ImportError: DLL load failed while importing lib
```

## Fix it
1. Reinstall pyarrow cleanly:
   ```
   pip install --force-reinstall pyarrow
   ```
   Expected: downloads and installs a fresh wheel.
2. Make sure the Visual C++ redistributable (2015 or later) is installed on the machine; pyarrow's DLLs need it. Expected: installer completes.
3. Verify:
   ```
   python -c "import pyarrow; print(pyarrow.__version__)"
   ```
   Expected: prints the version, no DLL error.

## When this applies
Use this when `import pyarrow` on Windows raises the DLL load failed message.

## When it does not apply
On Linux or macOS this specific message does not occur; look for the platform's own shared-library error. If a different DLL name is missing, install that component instead.

## Compatibility
Windows, pyarrow wheels with bundled native libs.

## Root cause
pyarrow ships compiled C++ libraries inside the wheel. If the wheel download was corrupt, partially overwritten, or the system C++ runtime is missing, Windows cannot load the bundled lib and Python surfaces this terse error.

## Edge cases
Antivirus quarantining the DLL mid-install causes repeat failures; reinstall with it paused if needed. Mixing pip and conda pyarrow in one env is a classic way to get mismatched native libs; pick one installer.