Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

When you run npm install or npm start and see package.json not fo...

How to Manually Remove a Stuck Git index.lock File
If Git operations suddenly fail with an error like fatal: Unable to create 'path/.git/i...

Fix npm run build Failed on macOS: Common Causes and Solutions
If you're on macOS and npm run build fails, you're not alone. This command o...

Fix npm run build Failures After npm install
After running npm install, you may find that npm run build fails with c...

Fix ERR_CERT_AUTHORITY_INVALID on Localhost
When testing a local web app, you may see ERR_CERT_AUTHORITY_INVALID in Chrome or si...

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