Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

When you see fatal: Unable to create 'path/.git/index.lock': File exists., G...

If you see a 'Secure Connection Failed' error in Firefox for Android, your browser cannot...

If you see the error error: externally-managed-environment when running pip in...

How to Fix Git Push Rejected (Non-Fast-Forward) Error
You run git push and get an error like ! [rejected] main -> main (non-fast-...

How to Fix Chrome Crash Loop on Windows and Mac
If Chrome opens for a few seconds and then crashes, or keeps restarting in a loop, you're lik...

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