Boot Diagnostic Black Screen Issue

Question

Hello all,

I have a virtual machine (Windows 2019 gen1) on Azure, i can connect RDP and this vm is running prod env. This vm have a problem about boot diagnostic. When I checked I see only black screen.

Can you help me?

Answer 1

Hello @Eda GOKBORA

If you are experiencing a black screen issue with Azure VM Boot Diagnostics, you can try these steps:

• Disable virtual display timeout In the guest operating system, make sure the virtual display timeout is disabled.
• For Windows, run the following command from elevated CMD powercfg /setacvalueindex SCHEME_CURRENT SUB_VIDEO VIDEOIDLE 0

For Windows VMs, the Azure provisioning agent is different than the VM agent. It runs the above command during provisioning for VMs created from a generalized image. You can see this event if you search for powercfg in C:\Windows\Panther\WaSetup.xml, which is the provisioning agent log. But since the provisioning agent does not need to run for VMs created from a specialized VHD, that is a scenario where you would need to run the powercfg command manually to disable the virtual display timeout. Also, it is possible to have a particularly old Azure VM created from generalized image that may not have it set because it was created before the provisioning agent was updated to disable the virtual display timeout.

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