Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

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Latest checklists

You try to install a Python package with pip, and get an error like error: externally-manag...

Resolve Python Package Version Mismatch Errors
You run pip install and see errors like “package A requires package B==1.0 but y...

Fix Node.js Heap Out of Memory Error in PM2
If you're running a Node.js application under PM2 and seeing FATAL ERROR: CALL_AND_RETR...

Fix VS Code 'Cannot Save File: Permission Denied' on Mac
You're editing a file in VS Code on your Mac, hit save, and get: 'Failed to save:...

Fix Cloudflare Wildcard Subdomain Not Working
If you've set up a wildcard DNS record in Cloudflare (e.g., *.example.com) but s...

How to Fix Nginx 502 Bad Gateway in Docker
If you're running Nginx as a reverse proxy inside Docker and seeing a 502 Bad Gateway error, ...