Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

If you see an error like fatal: Unable to create 'path/to/repo/.git/index.lock': Fi...

Fix DNS Probe Finished NXDOMAIN Caused by Antivirus Blocking
You try to load a website and see DNS_PROBE_FINISHED_NXDOMAIN in Chrome, or simi...

Nginx Configuration Test Failed: Fix Server Block Errors
When you run nginx -t and see "test failed" with a server block error, it us...

Fixing Cloudflare 521 Error: Origin Unreachable
When you see Cloudflare error 521, it means your origin server is refusing the connection from Cl...

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 VS Code Permission Denied Error Code 13
You open a file or run a task in VS Code and see Error: EACCES: permission denied, open ...