Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

If you see an error that Windows Defender won't start—or the service stops immediately—it's usual...

You try to send or receive email in Outlook and see an error: "Proxy authentication failed"

Fix Windows Security Offline Installer Fails
When installing Windows Security (formerly Windows Defender) offline, the installer may fail sile...

Fix BitLocker High Memory Usage on Windows 10
If your Windows 10 system feels sluggish and Task Manager shows that BitLocker-related processes ...

Fix Windows Security High Memory Usage
If you notice Windows Security (formerly Windows Defender) using excessive memory—sometimes hundr...

Fix OneDrive Sync Unavailable After Update
After a recent Windows or Office update, you might see “OneDrive sync is unavailable” or the sync...