Virtual Machine Cannot Start (Vmware) – ESX/ESXi – 5.0

How to Fix “Virtual Machine Cannot Start” on VMware ESX/ESXi

Virtual machines occasionally fail to start on VMware ESX or ESXi hosts, especially after an unexpected shutdown, storage issue, or interrupted migration. One common symptom is that the virtual machine remains in a “stuck in transition” state or displays a “Virtual Machine Cannot Start” error.

In many cases, the VM itself is healthy, but a stale VMX process is preventing VMware from powering it on. This guide explains how to identify the problem and safely recover the virtual machine.

Why Does This Error Occur?

A virtual machine may fail to start for several reasons, including:

• A previous VM process did not terminate correctly.
• The ESXi host experienced an unexpected reboot.
• A backup or snapshot operation was interrupted.
• The VM is locked by another process.
• Storage connectivity issues.
• Resource constraints on the host.

Before making changes, verify that the virtual machine is not already running on another ESXi host.

Step 1: Check the Virtual Machine Status

Log in to the ESXi host using SSH and identify the virtual machine process.

vim-cmd vmsvc/getallvms

Locate the VM ID of the affected virtual machine, then check its current power state.

vim-cmd vmsvc/power.getstate <VMID>

If the VM appears to be powered off but still cannot start, continue with the next step.

Step 2: Identify the Stuck VM Process

Check whether the virtual machine process is still running.

esxcli vm process list

If the VM is listed, note the World ID. Older ESX systems may also use:

ps | grep vmx

to identify active VM processes.

Step 3: Stop the Stuck Process

If the process remains active even though the VM is powered off, terminate it gracefully.

esxcli vm process kill --type=soft --world-id=<WorldID>

If the process does not stop, try:

esxcli vm process kill --type=hard --world-id=<WorldID>

Use the force option only as a last resort.

Step 4: Start the Virtual Machine

After terminating the stale process, start the virtual machine again using VMware vSphere Client, VMware Host Client, vCenter Server, or from the command line:

vim-cmd vmsvc/power.on <VMID>

The virtual machine should now power on successfully.

Additional Checks

If the VM still fails to start, verify the following:

• Storage Availability — confirm that the datastore is online and accessible.
• VM Configuration File — ensure the .vmx file exists and has not been corrupted.
• File Locks — verify that no lock files remain from previous operations.
• Snapshot Health — remove unnecessary snapshots if they are causing conflicts.
• Host Resources — check whether sufficient CPU, memory, and storage resources are available.

Best Practices to Prevent VM Startup Issues

To reduce the likelihood of virtual machine startup failures:

• Always shut down virtual machines gracefully.
• Keep ESXi hosts updated with the latest supported patches.
• Monitor datastore health regularly.
• Avoid leaving old snapshots for extended periods.
• Verify backup jobs complete successfully.
• Monitor ESXi logs for recurring storage or hardware issues.

Regular preventive maintenance can significantly reduce unexpected VM failures.

Conclusion

A “Virtual Machine Cannot Start” error on VMware ESX or ESXi is often caused by a stuck VM process rather than a damaged virtual machine. Identifying the running process, safely terminating it, and restarting the VM usually resolves the issue without affecting the guest operating system.

If the issue persists after following these steps, investigate datastore connectivity, VM configuration files, resource availability, and VMware logs to determine the underlying cause.

Frequently Asked Questions