After a custom image is applied, a VM restarts to a black screen and never reaches the login prompt. The administrator needs the fastest way to inspect what happened during boot without logging into the guest OS. What should be enabled or reviewed first?

Azure Monitor metric alert

Metric alerts can notify about symptoms, but they do not show detailed pre-login boot output from the VM.

VM extension status

Extension status is useful after the OS is running, but it does not show the initial boot screen contents.

Network Watcher IP flow verify

IP flow verification analyzes network paths, but this problem is about startup and boot-time visibility.

What does this AZ-104 question test?

Read the scenario before looking for a memorised answer.

What is the correct answer to this question?

The correct answer is: Boot diagnostics — Boot diagnostics is the fastest tool for this problem because it shows the VM console screenshot and serial log during startup, even when the guest OS never reaches the login screen. That makes it ideal for troubleshooting bad images, boot loader issues, or configuration changes that prevent a successful startup. It provides direct evidence of what the VM displayed before the OS became usable, which is more useful than alerts, extension status, or network tools in this case. Why others are wrong: Metric alerts can tell you that a VM is unhealthy, but they do not expose boot-time visuals or serial output. VM extension status only helps after the guest agent is available and the OS is running. Network Watcher IP flow verify is for traffic decisions, not for diagnosing a black-screen boot failure.

What should I do if I get this AZ-104 question wrong?

Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.