Checklists for software errors, setup, and tool workflows.

1. Reproduce

2. Isolate

3. Apply

4. Verify

Latest checklists

You try to activate Windows or install an update, and get error 0x80070003. It often means Window...

If Windows Defender (Microsoft Defender Antivirus) is acting up—won't open, shows error messages,...

If Windows Security won't open, shows errors, or you see "This app has been turned off" messages,...

When installing or updating apps from the Microsoft Store, you might see an error saying the setu...

Windows Defender syncs security settings and scan history across your devices through your Micros...

You downloaded the Windows Security offline installer but it won't run, hangs, or throws an error...