Unable to expand a virtual machine's hard disk

Products

• VMware vSphere ESXi

Issue/Introduction

1. When attempting to expand the size of a virtual machine's hard disk (vmdk) in the "Edit Settings" screen, the hard disk size is grayed out and expansion is not possible.
   
   or
   
   The expansion of the vmdk fails with the error: "The disk extend operation failed. The virtual disk requires a feature not supported by this program, Hot extend is currently supported only for VMFS flat virtual disks without snapshot opened in persistent mode."
   
   

2. If you expand the view of the hard disk item whose size is grayed out, you will see that the snapshot file is listed as a "Disk File".

   Example of a display if a snapshot file is listed as a "Disk File":
   [DatastoreName]VirtualMachineName/VirtualMachineName-000001.vmdk

   Example of a display if a snapshot file is not listed as a "Disk File":
   [DatastoreName]VirtualMachineName/VirtualMachineName.vmdk

Environment

VMware vSphere ESXi (All versions)

Cause

This issue occurs when snapshots exist for the target virtual machine.

Resolution

1. Snapshot Consolidation:
   • Right-click the VM and select Snapshots > Consolidate.
   • If the "Consolidate" option is missing or fails, take a new manual snapshot and then select Delete All Snapshots.
2. VM Cloning (Workaround if the snapshot chain is not healthy and Option 1 is not possible):
   • Power off the virtual machine.
   • Clone the affected VM to a new destination.
   • Verify the new VM, then decommission the original.

Note: Cloning reads the block-level state and creates a single, consolidated base disk, bypassing the broken metadata chain.

 

 

Additional Information

For more information on deleting/consolidating snapshots:

Consolidate Snapshots

Delete a Snapshot

FAQ: Delete all Snapshots and Consolidate Snapshots Feature