Python package UnicodeDecodeError in Virtual Environment on FAT Filesystem

Problem

When attempting to interact with Python packages (listing, updating, installing, etc.) via PyCharm, an error occurs. The error is specifically related to a UnicodeDecodeError: 'utf-8' codec can't decode byte 0xb0 in position 37: invalid start byte. This happens while using a virtual environment located on a FAT-formatted volume.

Cause

The issue arises because the FAT filesystem is not fully compatible with the way Python handles files in virtual environments.

Resolution

The recommended solution is to recreate the virtual environment on the internal macOS drive, where the filesystem (APFS/HFS+) handles Python's requirements more effectively.

Steps to Resolve:

1. Create a new virtual environment on the internal macOS drive using the following commands:

   python3 -m venv ~/.virtualenvs/newvirtualenv
   source ~/.virtualenvs/newvirtualenv/bin/activate
   pip install -r /Volumes/SRC/directory/newvirtualenv/requirements.txt
   

2. In PyCharm, navigate to Settings | Python | Interpreter, then:
   • Click Add Interpreter.
   • Select Add Local Interpreter.
   • Choose Select Existing and point it to the newly created virtual environment (e.g., ~/.virtualenvs/newvirtualenv/bin/python).

This workaround isolates the virtual environment from the limitations of the FAT filesystem while preserving your project structure on the external drive.