# selenium.common.exceptions.SessionNotCreatedException: Message: session not created: This version of ChromeDriver only supports Chrome version 121

- **ID:** `python/pytest-selenium-webdriver-manager-fail`
- **Domain:** python
- **Category:** install_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The installed ChromeDriver version doesn't match the local Chrome browser. This commonly happens after an automatic Chrome update without a corresponding driver update.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 4.15.x | active | — | — |
| 4.20.x | active | — | — |

## Workarounds

1. **** (94% success)
   ```
   from selenium import webdriver
from selenium.webdriver.chrome.service import Service

# Selenium Manager handles driver download automatically
driver = webdriver.Chrome()  # no Service path needed
   ```
2. **** (90% success)
   ```
   from selenium import webdriver
from selenium.webdriver.chrome.service import Service
from webdriver_manager.chrome import ChromeDriverManager

driver = webdriver.Chrome(service=Service(ChromeDriverManager().install()))
   ```

## Dead Ends

- **** — Works until Chrome auto-updates again; brittle and requires manual re-pinning per machine. (70% fail)
- **** — Headless mode doesn't bypass the version check; the SessionNotCreatedException is raised before browser launch. (80% fail)