VM power-on task hangs at 66 percent with general system error

Products

• VMware vSphere ESXi

Issue/Introduction

Virtual machines may fail to power on, with the task status in vCenter Server remaining at 66 percent and eventually timing out with the error "A general system error occurred." This behavior often indicates that the virtual machine process on the ESXi host is unresponsive or that the disk chain is locked due to a disrupted snapshot state.

Symptoms:

• Power-on task hangs at 66% in vCenter Server.
• vCenter Server displays: "A general system error occurred."
• VM process on the ESXi host is unresponsive to standard power operations.

Cause

A hung virtual machine process on the ESXi host creates a file lock on the datastore. If this process is terminated forcefully, lingering snapshot files may cause a race condition, preventing the hypervisor from granting read/write access to the virtual disk chain.

Resolution

1. Log in to the affected ESXi host via SSH.
2. Identify the hung VM process: esxcli vm process list
3. Terminate the unresponsive process using the World ID obtained from the previous step: esxcli vm process kill -t force -w ####
4. Perform snapshot consolidation:
   • Navigate to the virtual machine directory on the datastore.
   • Trigger the snapshot deletion or consolidation task via the vSphere Client.
5. Verify disk chain consistency for the base disk (e.g., ####.vmdk): vmkfstools -e ####.vmdk
6. Confirm block-level integrity of the virtual disk: vmkfstools -x check ####.vmdk
7. Verify the .vmx configuration file correctly points to the base disk.
8. Power on the virtual machine via vCenter Server.
9. Initiate a full backup job to ensure the current system state is protected.