1. Resource Conflicts & State Issues

If you try to start a VM and receive an error indicating the resource is "already being used" or the state prevents the action, check the following:

Boot Disk Operations in Progress

When an operation like snapshot creation or disk cloning is running on the VM's boot disk, the disk is temporarily locked, preventing the VM from starting.

• Symptom: You see an error like: "Failed to start example-vm: The instance resource '...' is already being used by '.../disks/clone'".

• Fix:

  1. Go to the VM instances page and check the Notifications pane or the Activity tab for pending operations.

  2. Wait a few minutes for the snapshot or clone to complete.

  3. Once the operation is finished, retry starting the VM.

Incorrect Instance State

• Symptom: The console shows a spinning wheel or you receive an error about being unable to start because it's "not stopped."

• Fix: If the VM is stuck, try a hard reset using the gcloud CLI
  command, which can sometimes clear a bad state.
  Bash

  gcloud compute instances reset [VM_NAME] --zone=[ZONE]
  

  After the reset completes (which is like a hard power cycle), try the start command again.

2. Diagnosing Boot Disk Failures

If the VM successfully moves to the RUNNING state but you can't connect (e.g., SSH fails), the issue is likely within the operating system (OS) boot process.

Examine the Serial Console Output

• Action:

  1. In the Google Cloud Console, navigate to Compute Engine > VM instances.

  2. Click on the problematic VM name.

  3. Go to the Serial port 1 (Console)
     tab.

  4. Review the output for errors such as kernel panics, filesystem errors, or messages about boot failure.

Boot Disk is Full or Corrupted

• Symptom: Serial console output shows errors related to mounting the root filesystem or running out of disk space.

• Fix (Requires a Rescue VM):

  1. Stop the problematic VM.

  2. Create a snapshot of the boot disk for safety, then detach the boot disk.

  3. Create a new, temporary VM (your rescue VM
     ) in the same zone

  4. Attach the original VM's boot disk
     as a secondary disk to the rescue VM.

  5. SSH into the rescue VM, mount the attached disk, and perform one of the following:

     • If full: Delete unnecessary files to free up space, or resize the disk (which you can do directly from the Compute Engine Disks
       page).

     • If corrupted: Run a file-system check (fsck
       ) to repair errors on the disk.
  6. Unmount and detach
     the disk from the rescue VM.

  7. Attach the disk back as the boot disk to the original VM, and try to start it.

3. Resource & Zone Availability

• Symptom: You receive an error like: "The zone 'projects/...' does not have enough resources available to fulfill the request. Try a different zone, or try again later."

• Fix:

  • Wait and Retry: Resource availability is dynamic. Try starting the VM again after a few minutes.

  • Migrate the VM: Move the VM instance to a different zone
    within the same region where resources are available.
    You can use the gcloud compute instances move command or manually re-create the VM from its boot disk in a new zone.

  Bash

  gcloud compute instances move [VM_NAME] \
      --zone=[OLD_ZONE] \
      --destination-zone=[NEW_ZONE]
  

4. Permissions and IAM Issues

If you are using a service account or non-default credentials to start the VM, insufficient IAM permissions can prevent the action.

• Symptom: The console displays an "Insufficient permissions" error or an error mentioning a lack of permission like compute.instances.start.

• Fix:

  1. Verify that your user account or the service account being used has the necessary Compute Engine roles, such as Compute Instance Admin (v1) or a custom role that explicitly grants the compute.instances.start
     permission.

  2. If the VM's Service Account is involved, ensure it has the necessary Access scopes (e.g., "Compute Engine API access" set to Read/Write
     or Full).