VMDK disk show zero size after snapshot operation

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

After taking or consolidating a snapshot on a virtual machine, the task completes successfully. However, the VM configuration shows the VMDK disk size as “0” (zero).

Additional symptoms that may occur include:

• Unable to perform any task on the virtual machine.
• Backup jobs failing for the virtual machine.

• The following errors may appear in /var/run/log/hostd.log on the ESXi host:
  YYYY-MM-DDTHH:MM:SS.743Z warning hostd[1B4C2B70] [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/-######-695f-/x/x.vmx] Snapshot create succeeded, but UID 650 not in list.
  YYYY-MM-DDTHH:MM:SS.743Z warning hostd[1B4C2B70] [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/-######-695f-/x/x.vmx] Failed operation
  YYYY-MM-DDTHH:MM:SS.744Z info    hostd[1B4C2B70] [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/-######-695f-/x/x.vmx] State Transition (VM_STATE_CREATE_SNAPSHOT -> VM_STATE_ON)
  YYYY-MM-DDTHH:MM:SS.744Z info    hostd[1B4C2B70] [Originator@6876 sub=Vimsvc.TaskManager] Task Completed : haTask-49-vim.VirtualMachine.createSnapshot-127313764 Status error
  YYYY-MM-DDTHH:MM:SS.595Z warning hostd[1B4C2B70] [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/-######-695f-/x/x.vmx] UpdateStorageAccessibilityStatusInt: The datastore is not accessible ide1:0.fileName = "/vmfs/volumes/-######-7681-/contentlib--0b4f-4c5b-bc5b-/-4f37-47e9-aa1e-/x.iso"
  

 

Environment

 

VMware vSphere ESXi 7.0.x

VMware vSphere ESXi 8.0.x

Cause

The ESXi host service (hostd) treats a virtual machine as a single managed object, even though the VM consists of multiple underlying files.

If any of the VM’s child components (such as an ISO, virtual disk, or descriptor file) becomes inaccessible, the VM can transition to an invalid load state.

Common causes include:

• An ISO file attached to the VM being deleted or moved without detaching it first.
• The datastore containing the VM files becoming temporarily inaccessible.

When the datastore is unavailable, hostd fails to refresh the disk information. In such cases, it creates placeholder entries with zero capacity for uncached virtual disks. Consequently, snapshot creation may fail because the system cannot locate the new UUID in the snapshot list.

Although the snapshot process starts successfully, it fails during the verification step, generating the “UID not in list” error seen in the logs.

Resolution

 

• Migrate the VM to another ESXi host to refresh hostd metadata.
• If the issue persists, verify datastore accessibility:
  • • Confirm that the datastore containing the VM’s files is accessible.
    • Resolve any storage or connectivity issues before proceeding.
      
      
• Refresh the VM configuration by performing one of the following actions:
  Option 1 – Reload the VM via SSH:
  
  1. SSH into the ESXi host where the VM resides.
  2. Identify the VM ID (VMID):
     vim-cmd vmsvc/getallvms | grep <VM_name>
      
  3. Reload the VM:
     vim-cmd vmsvc/reload <VMID>

  Option 2 – Re-register the VM via vSphere Client:

  1. Right-click the affected virtual machine and select Remove from Inventory.
  2. In the datastore browser, navigate to the VM’s directory.
  3. Locate the .vmx file, right-click, and select Register Virtual Machine.
      
• Check for and remove inaccessible ISOs:
  
  • Edit the VM’s settings in the vSphere Client.
  • Detach any ISO files that are marked as inaccessible or unavailable.

 Note: After completing these steps, recheck the VM configuration. The disk size should now appear correctly, and snapshot tasks should function normally.