Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

If your Mac slows down when Chrome is open, or you see high memory usage in Activity Monitor, you...

If you see fatal: Unable to create 'path/to/.git/index.lock': File exists., ...

You're working in a subdirectory of your project, run npm install or npm r...

How to Fix Git Detached HEAD and Checkout a Branch
You're working in a Git repository, make some commits, and then realize you're in a '...

Fixing Nginx Upstream Connection Refused and Permission Denied
If you see connect() failed (111: Connection refused) or connect() failed (13:...

Fix Chrome ERR_CONNECTION_RESET Due to Proxy Settings
You're browsing in Chrome and suddenly pages won't load, showing ERR_CONNECTION_R...