Revert to snapshot causes virtual machine to be suspended

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

If you take a snapshot of the virtual machine and then VMotion or cold-migrate the virtual machine to another host that uses a different CPU model and/or family, you may experience the following symptoms:

• The virtual machine becomes stuck in a suspended state after performing a Revert to Snapshot operation
• If you try to remove the virtual machine from its suspended state, you see the error:
  
  Error: error encounter trying to restore cpu state from file.

Environment

VMware VirtualCenter 2.0.x
VMware ESX Server 3.0.x

Resolution

This issue may occur if the CPU information as recorded in the virtual machine configuration file (.vmx) after the Revert to Snapshot operation does not match the current CPU information. If this occurs, the server does not un-suspend the virtual machine.

To resolve this issue, you must remove the checkpoint.* lines from the .vmx file. Removing these lines allows you to power on the virtual machine.

To remove the checkpoint.* lines:

1. Ensure that the virtual machine is not running another process.
2. Unregister the virtual machine.
3. Open the .vmx file in a text editor.
4. Remove the checkpoint.* lines from the file.
5. Save and close the file.
6. Re-register the virtual machine.
   
   The virtual machine is in a powered off state. You can now power it on.

Note: This procedure may remove your snapshot tree from the snapshot manager. If the snapshot manager shows no snapshot but the virtual disks are pointing to snapshot disks, they should be consolidated. For more information, see Committing snapshots when there are no snapshot entries in the snapshot manager (1002310).