Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

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

Fix Node Sass Build Failure: Environment Variable Errors
When you run npm install or a build script and see an error like Node Sass doe...

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

Fixing Docker Build Context Canceled Permission Denied
You're running a Docker build, and suddenly it fails with an error like context cancele...

How to Fix ERR_CONNECTION_RESET in Chrome
If you see ERR_CONNECTION_RESET in Chrome, the browser can't establish a con...

Fix 'python command not found' After Windows Upgrade
After upgrading Windows 10 to 11 (or a major feature update), many users find that typing p...