Fixing Chrome Automation Crashes: How I Solved Profile Lock Conflicts
Why My Chrome Windows Kept Disappearing
During the day, I take care of my six-year-old child. At night, I build AI-driven blog automation and product lookup tools to make a living.
Recently, a frustrating bug cropped up where my blog drafting script and product scraping tool kept force-closing each other's Chrome windows. I lost unsaved drafts in my editor more than once when tabs vanished without warning.
The culprit turned out to be simple. Running multiple Chrome processes that pointed to the exact same user data directory caused file-locking collisions, crashing the browser sessions.
Debugging with Claude: Ports and Locking Mechanisms
I took the issue to Claude, the AI assistant, to figure out a cleaner architecture. My initial quick fixes, like tweaking basic Chrome options or adding arbitrary wait times, failed completely.
The breakthrough came from changing how the browser launched. Instead of opening a brand-new instance every time, I started Chrome once with a remote debugging port and configured subsequent scripts to attach to that existing port.
To keep tasks from stepping on each other, I combined inter-process file locks with in-app re-entrant locks into a single session context. It took several rounds of back-and-forth prompts to get the logic right.
A Single Wrapper for Shared Browser Sessions
The final setup allows multiple automated scripts to share one Chrome instance safely. When multiple tasks trigger at once, the locking mechanism queues them so only one script touches the browser at a time.
Implementation is straightforward: I just wrap existing routines in a single session context manager line in the code.
Since switching to this setup, unexpected session drops and sudden logouts have stopped entirely.
Key Takeaways for Running Multiple Selenium Scripts
This setup has one caveat: inter-process file locks are most reliable within the same local environment or container, and external interventions can disrupt task ordering.
However, if you run multiple automation tools side by side, you will almost certainly run into Chrome profile collision errors.
Instead of spawning fresh browser instances with identical profile folders, launch one instance on a debugging port and enforce task-level locks.
Common questions
Why does Selenium crash when running multiple scripts with the same Chrome profile?
Chrome locks its user data directory while running. If a second Selenium process tries to access the same directory simultaneously, the file-lock conflict crashes the browser.
How do you share one Chrome window across multiple automation scripts?
You can launch Chrome with a remote debugging port (like --remote-debugging-port=9222) and configure your scripts to attach to that port instead of spawning new instances.
How do you prevent scripts from colliding while using the same Chrome instance?
Wrap your automation jobs in a context manager using inter-process file locks, which ensures only one script controls the shared browser at any given moment.