Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

If you're working with Git on a Mac and see the error fatal: Unable to create '/pat...

Fix ERR_CONNECTION_RESET in Chrome: Network Settings Guide
If Chrome shows ERR_CONNECTION_RESET when you try to load a page, the connection was...

Fix 'Python' Command Not Found After Reinstall on Windows
You reinstalled Python on Windows, but when you type python in Command Prompt, you g...

Fix Nginx 'upstream connection refused' When Talking to PHP-FPM
You're seeing upstream connection refused in your Nginx error log, and your site...

Fix Python UnicodeDecodeError for sys.stdin Input
When you run a Python script that reads from standard input and get UnicodeDecodeError: ...

Fix Cloudflare 521 Error Due to Server Overload
You see a Cloudflare 521 error page. The message says the web server is down. Often, this means y...