Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

You see a Cloudflare 521 error page. The message says the web server is down. Often, this means y...

You run npm install and get a wall of red: ENOENT: no such file or directory, ...

Fix 'Permission Denied' When Running pip install --user
If you see Permission denied when running pip install --user somepackage

Fix Nginx Configuration Test Syntax Errors
When you run nginx -t and see syntax error, the nginx service will ...

Fix Git 'index.lock' File Exists Error in SourceTree
If you use SourceTree and see an error message like fatal: Unable to create 'path/to/.g...

Fix pip Externally Managed Environment Error on Linux
If you're seeing error: externally-managed-environment when trying to pip ...