ModuleNotFoundError: No module named 'mechanicalsoup'

Not specified by the original author.

MechanicalSoup is not installed in the running Python. Run python -m pip install mechanicalsoup. The PyPI name and the import name are both mechanicalsoup (all lowercase, one word), so there is no dash/underscore trap.

The error

ModuleNotFoundError: No module named 'mechanicalsoup'

Fix it

1. Install MechanicalSoup

python -m pip install mechanicalsoup

Expected: Successfully installed mechanicalsoup-... with beautifulsoup4, lxml, and requests.

2. Confirm

python -c "import mechanicalsoup; b = mechanicalsoup.StatefulBrowser(); print('ok')"

Expected: prints ok.

When this applies

• any mechanicalsoup import fails naming mechanicalsoup
• a fresh env or a script moved to a new machine

When it does NOT apply

• errors naming bs4 or html5lib mean MechanicalSoup IS installed but a dependency is broken
• cannot import name 'StatefulBrowser' on very old installs means pre-1.0 API (upgrade)

Compatibility

MechanicalSoup 1.x current. Needs Python 3.8+. The main class is StatefulBrowser (the old Browser was renamed in 1.0).

Why it happens

The package was never installed into the active interpreter. Form-filling scraper scripts are frequently copied between machines without their requirements, and the import is the first line that notices.

Edge cases

• Old tutorials use mechanicalsoup.Browser. On 1.x that name is gone; use StatefulBrowser.
• If the import succeeds but form submission misbehaves, that is runtime behavior, not this error.

In gh:mobeigi/fb2cal#71 the reporter hit ModuleNotFoundError: No module named 'mechanicalsoup' running fb2cal, fixed by installing MechanicalSoup into the environment. Standard missing-install report. Source: https://github.com/mobeigi/fb2cal/issues/71