Checklists for software errors, setup, and tool workflows.

Docker Container Exits Immediately on Windows: How to Fix

You start a Docker container on Windows, and it stops within seconds. The container exits immedia...

Cloudflare DNS Propagation: How to Check and Fix Delays

When you change DNS records on Cloudflare, propagation can take longer than expected. This articl...

Fix Nginx Upstream Connection Refused Error

When Nginx returns upstream connection refused in your error logs, it means Nginx tr...

Fix Windows Security App Missing from Start Menu

You open the Start menu, type “Windows Security,” but nothing appears. The app may have been unre...

Nginx Upstream Connection Refused: Diagnosis and Fixes

When Nginx returns a 502 Bad Gateway or logs "upstream connection refused", it means Ngin...

How to Fix Git Merge Unrelated Histories Error

You run git pull or git merge and get:

fatal: refusing to...