Checklists for software errors, setup, and tool workflows.

Fix Jupyter Notebook Token Not Working on Ubuntu

You launch Jupyter Notebook on Ubuntu, but when you open the URL in your browser, the token promp...

Windows Activation Failed Due to Blocked Key: Fixes That Work

You see “Windows activation failed due to blocked key” – it usually means the product key you’re ...

How to Temporarily Turn Off Windows Security for Troubleshooting

If you're troubleshooting a stubborn app or driver issue, Windows Security (formerly Defender) mi...

How to Fix Windows Defender Version Mismatch on Windows 10

You might see an error saying Windows Defender has a version mismatch, or the app won't open beca...

How to Fix Windows Security Service Unavailable

When Windows Security shows "Service unavailable" or a red banner, your antivirus and firewall pr...

Fix Docker Build Error: 'failed to solve: manifest not found'

You run docker build and get an error like:

failed to solve: error fetching ...