ESXi/ESX host boot halts with the error: Error panic:cannot open b.z

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• ESXi/ESX host boot or reboot halts.
• When booting or rebooting an ESXi/ESX host, you see this error on the console:
  
  Error panic: cannot open b.z

Cause

This issue is caused by a corrupt boot partition or multiple failed upgrades or installations.

Resolution

To resolve this issue, create a bootable CD/DVD and reboot the host.

 

To create a bootable CD/DVD and reboot the host:

1. Download a copy of the ESX/ESXi installation media from VMware Download Center and burn it onto a CD/DVD.
2. Place the CD/DVD into the affected system.
3. Reboot the host.
4. Boot off of the Physical Media and perform an in-place upgrade.

If these steps fail, perform a fresh installation of the ESX/ESXi host. For more information, see the:

• vSphere 5.1 Installation and Setup Guide
• vSphere 5.0 Installation and Setup Guide
• ESXi and vCenter Server Setup Guide

Additional Information:

• "Configuration Upgrade Failure" after reboot of upgraded ESXi 7.0 host ​​​​​​​