Hi, I opened https://github.com/pantsbuild/pex/issues/785 to track an issue where user environment leaked into pex virtual environment. When pex constructs the minimum_sys_modules, it only drops tainted modules which is a package (with path) but keeps the ones which doesn't have path. This will leave some residual from user's environment into the pex virtual environment, for example modules like

Jinja2.utils

. Also submitted a PR for possible fix: https://github.com/pantsbuild/pex/pull/786/files Please help taking a look