A VM will not boot with a virtual disk that has a missing VMFS flat file.

Products

• VMware vSphere ESXi

Issue/Introduction

A VM's virtual disk is missing and will not allow it to boot.  Inspection of the VM's folder on the datastore may show that the VMDK descriptor file and corresponding -flat.vmdk file is also missing.  The .vmx file would still have reference to the missing virtual disk, thus it is not found on boot and that fails.  

Environment

VMware vSphere ESXi (All Versions)

Cause

The inconsistency can manifest in a number of ways.  One way a VM can be left in an inconsistent state is a failed backup operation.  Typically there would only be stale locks or an inconsistent snapshot chain.  In rare situations the descriptor and flat file might be inadvertently removed.

Resolution

For situations where the flat file is missing, there is no possible method for restoring the disk by vSphere operations.  The virtual disk would need to restored from a backup.