Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

You try to run a Git command and see fatal: Unable to create 'path/.git/index.lock'...

Fix Node.js Heap Out of Memory on Linux Server
If your Node.js application crashes on a Linux server with FATAL ERROR: Ineffective mark-co...

Fix Git index.lock File Exists Permission Denied Error
You're in the middle of a Git operation and suddenly you see:
fatal: Unable to ...

Fix Nginx 502 Bad Gateway with Docker and PHP-FPM
You have a Docker setup with Nginx proxying to a PHP-FPM container, and you're getting a 502 ...

Why npm Says 'package.json Not Found' and How to Fix It
You run npm install or npm start and get npm ERR! package.json no...

Windows 11 Update Stuck at 0%: Manual Download Fix
You click 'Check for updates' in Windows 11, and it hangs at 0% for minutes or hours. Res...