Vm is refusing to start

Question

VM is refusing to start; it stops but doesn't start. I tried to change the size of a disk attached to VM, I don't know if it' because it's LRS.

Answer 1

Hi Kelechi,

Thank you for reaching out on Q/A. Based on the details provided, your VM stops but does not start after the attempted disk size change. Please follow the troubleshooting steps below:

Note: Before performing any activity, ensure you have a backup of your data to avoid any potential data loss. It is recommended to create a snapshot of the disk before proceeding.

1. Check if the VM shows as Running in the Azure portal. This helps confirm whether the VM is stuck in a starting or stopped state.

2.Navigate to VM >> Activity Logs in the Azure portal to identify any errors related to VM start or disk attachment.

Reference: Activity log in Azure Monitor

3.Enable Boot Diagnostics to capture screenshots and logs of the VM boot process. This can help identify OS-level or disk-related boot issues.

Reference: How to use boot diagnostics to troubleshoot virtual machines in Azure

4.Try updating the VM configuration using Azure CLI:

az vm update -n "VM_NAME" -g "RG_NAME"

This can sometimes resolve minor provisioning inconsistencies.

Reference: https://learn.microsoft.com/en-us/cli/azure/vm?view=azure-cli-latest#az_vm_update

5. If the VM still does not start, try Redeploy or Reapply from the Azure portal. This moves the VM to a new host and re-applies provisioning, resolving many stuck-start issues.

Reference: Troubleshoot deployment issues with restarting or resizing an existing Windows VM in Azure

6.Deallocate and Create a New Disk (if required)

If the VM continues to fail, deallocate the VM and create a new managed disk from a snapshot or backup. Then attach the new disk to the VM and attempt to start.

Steps:

1. Take a snapshot of the OS disk:
   • Navigate to Virtual machines → select your VM → Disks
   • Click the OS disk name → Create snapshot → specify Snapshot name, Resource group, Snapshot type (Standard SSD/Premium SSD) → Review + create
2. Create a disk from the snapshot:
   • Go to Snapshots → Create Disk → Enter Name and required details → Create
3. Create a new VM from the managed disk:
   • Go to Disks → select the snapshot disk → Create VM → Fill in the details → Create

Reference:

Create a virtual machine from a snapshot with CLI

Create a snapshot of a virtual hard disk

Create a VM from a specialized disk

Create a virtual machine using an existing managed OS disk

We hope this helps resolve the issue. Please share any error messages or logs if the problem persists so we can provide further assistance.

Additionally, could you please check the private message and provide the necessary details