Checklists for software errors, setup, and tool workflows.

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Fix DNS Probe Finished NXDOMAIN After Changing DNS

After updating your DNS settings—perhaps to use Google Public DNS or Cloudflare—you might see the...

How to Generate a Cloudflare Origin Certificate

If you're using Cloudflare as a reverse proxy, you may want to encrypt traffic between your s...

How to Fix Cloudflare Origin Certificate Invalid Error

If you see a Cloudflare origin certificate invalid error, your browser or server is rejecting the...

How to Create a package.json for Your npm Project

If you're starting a Node.js project, you'll need a package.json file. This ...

Fix pip Externally Managed Environment Errors

If you're on a modern Linux distribution and see error: externally-managed-environment<...

How to Fix Windows Update Error 0x800f081f (Missing Files)
You see error 0x800f081f when running Windows Update, often with a message like 'The source f...