Python venv Troubleshooting Cheat Sheet

which python

# See which python binary your shell resolves first.

which pip

# See which pip binary your shell resolves first.

command -v python

# Portable shell check for command resolution.

python -c "import sys; print(sys.executable)"

# Verify the exact interpreter the shell is using.

python -m pip install -r requirements.txt

# Avoid ambiguity by tying pip to the active interpreter.

source .venv/bin/activate

# Source the activate script in bash or zsh.

source .venv/bin/activate.fish

# Source the fish activation script.

.venv\Scripts\Activate.ps1

# Activate from PowerShell.

Set-ExecutionPolicy -Scope CurrentUser RemoteSigned

# Fix execution policy for venv activation scripts.

rehash

# Force zsh to refresh remembered command paths.

python -m ensurepip --default-pip

# Bootstrap pip into the current interpreter or venv.

python -m ensurepip --upgrade

# Reinstall or upgrade pip from the standard library bundle.

python -m pip install --upgrade --force-reinstall pip setuptools wheel

# Refresh core package tooling in the venv.

python -m pip cache purge

# Clear cached artifacts before retrying installs.

rm -rf .venv && python -m venv .venv && source .venv/bin/activate && python -m pip install -U pip setuptools wheel && python -m pip install -r requirements.txt

# Start fresh from requirements.

Remove-Item -Recurse -Force .venv; py -m venv .venv; .venv\Scripts\Activate.ps1; python -m pip install -U pip setuptools wheel; python -m pip install -r requirements.txt

# Rebuild from scratch on Windows.

python -c "import pkgutil; print('requests' in [m.name for m in pkgutil.iter_modules()])"

# Smoke-test a rebuilt environment quickly.