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Recover data from damaged or formatted VMFS disks or VMDK files
Last updated: Jan 05, 2024

UEFI booting of ESXi fails and does not progress beyond VM Hypervisor Recovery

Facing challenges with UEFI booting in ESXi, particularly when it stops at the VM Hypervisor Recovery stage, can be a major hindrance for IT experts overseeing virtualized systems. This article aims to unravel the typical reasons behind such booting difficulties and offers an exhaustive guide for diagnosing and fixing these issues. We will go through crucial troubleshooting procedures, necessary configuration changes, and practical advice to guarantee that your ESXi hosts boot effectively in a UEFI setup. This ensures the continued stability and performance of your virtual infrastructure.

How to manually install a UEFI boot loader from an ESXi ISO installer image to recover the system

Manually installing a UEFI boot loader from an ESXi ISO installer image to recover the system can be a complex process, but it's achievable with careful steps. Here's a general guide to assist you:


  1. 1. ESXi Installer ISO: Obtain the latest version compatible with your system.
  2. 2. Access to the Server: Ensure physical or remote access to the server that needs recovery.
  3. 3. Bootable USB Creation Tool: A tool like Rufus or UNetbootin for creating a bootable USB.
  4. 4. A Blank USB Drive: To create a bootable ESXi installer.


1. Create a Bootable ESXi Installer USB

  • Download ESXi ISO: Get the ESXi installer ISO from the VMware website.
  • Prepare USB Drive: Insert a blank USB drive into a working computer.
  • Create Bootable Drive: Use a tool like Rufus to create a bootable USB drive with the ESXi ISO.

2. Boot from the USB Drive

  • Insert USB Drive: Place the bootable USB drive into the server needing recovery.
  • Access BIOS/UEFI Settings: Restart the server and enter the BIOS/UEFI settings (usually by pressing a key like F2, Del, or Esc during boot).
  • Set Boot Order: Ensure the boot order is set to start from the USB drive. Save changes and exit BIOS/UEFI.

3. Install/Recover ESXi

  • Boot from USB: The server should now boot from the USB drive, loading the ESXi installer.
  • Follow Installation Prompts: Go through the ESXi installation process. When prompted, select the option to install or upgrade.
  • Choose Target Disk: Be cautious at this stage. Select the correct disk where you want to install or recover ESXi. If recovering, the installer might detect existing ESXi installations.

4. Install UEFI Boot Loader

  • Complete Installation Process: The installer will install the necessary files, including the UEFI boot loader.
  • Reboot System: Once installation is complete, remove the USB drive and reboot the system.

5. Post-Installation Checks

  • Verify Boot: Ensure the system boots correctly into ESXi.
  • Configure Settings: If it's a new installation, you may need to configure network settings, hostname, etc.


  • Backup Data: If this is a recovery operation, ensure you have backups of critical data.
  • Check Compatibility: Ensure your hardware is compatible with the ESXi version you're installing.
  • Firmware Update: Sometimes, updating the server's firmware can resolve boot issues.


  • This process can erase data on the target disk. Proceed with caution and ensure you're working on the correct disk.
  • If you're unsure at any stage, it's advisable to consult with a professional or refer to VMware's official documentation for guidance.

Remember, each server environment can be unique, so these steps might need adjustments based on your specific situation.

Causes of UEFI booting of ESXi fails

When UEFI booting of ESXi fails, it can be due to several reasons, often related to hardware compatibility, configuration issues, or problems with the boot media. Understanding these causes can help in troubleshooting and resolving the boot issues. Here are some common causes:

1. Incompatible Hardware:

  • UEFI Firmware Compatibility: Not all hardware, especially older models, fully supports UEFI or might have outdated UEFI firmware that is incompatible with newer ESXi versions.
  • Hardware Failures: Issues with the server's hardware components, like a failing hard drive, corrupt memory, or motherboard problems, can also cause boot failures.

2. Improper Configuration:

  • BIOS/UEFI Settings: Incorrect BIOS/UEFI settings can prevent proper booting. This includes the boot mode (legacy vs. UEFI), secure boot settings, and the boot order.
  • Disk Partition Style: ESXi expects a certain partition style (GPT for UEFI). If the disk is not correctly formatted or partitioned, it won't boot.
  • Corrupt NVRAM Entries: Sometimes, the NVRAM on the motherboard, which stores boot configuration data, can become corrupt, leading to boot issues.

3. Issues with the Boot Media:

  • Corrupt Installation Media: If the ESXi installer media is corrupt or improperly created, it won't boot correctly.
  • Incompatible File System: UEFI systems require a FAT32 file system for the EFI partition. If this is not correctly set up, it will fail to boot.

4. Software Problems:

  • Corrupted ESXi Installation: A damaged or incomplete ESXi installation can result in boot failures.
  • Outdated ESXi Version: Sometimes, the ESXi version is too old to support UEFI or certain hardware configurations.

5. Secure Boot Issues:

  • Secure Boot Incompatibility: Secure Boot is a UEFI feature that ensures that only signed bootloaders can boot. If the ESXi bootloader isn't recognized or if there's a mismatch in the signatures, the boot process can fail.

6. Network Boot Environments:

  • PXE Boot Misconfiguration: In environments where PXE (network boot) is used, misconfiguration or network issues can prevent a successful boot.

Preventive Measures and Solutions:

  • Firmware Updates: Keeping the server's BIOS/UEFI firmware updated can resolve many compatibility issues.
  • Correct Configuration: Ensure BIOS/UEFI settings are correctly configured for UEFI booting.
  • Check and Recreate Boot Media: Verify the integrity of the ESXi installation media and recreate it if necessary.
  • Review Hardware Compatibility: Check VMware's hardware compatibility list to ensure the server is supported.
  • Troubleshoot Secure Boot: If using Secure Boot, ensure it is correctly configured or try disabling it to see if that resolves the issue.

When facing UEFI boot issues with ESXi, a systematic approach to checking each of these areas can help identify and resolve the problem. If the issue persists, consulting VMware's documentation or seeking assistance from VMware support can be beneficial.

Solution of UEFI booting of ESXi fails

DiskInternals VMFS Recovery is a specialized software solution designed to assist with data recovery from VMFS (Virtual Machine File System) used by VMware. While it is primarily focused on recovering data from VMFS volumes, it may not directly resolve UEFI booting issues of ESXi. However, it can be a valuable tool in scenarios where the ESXi host fails to boot, and there's a need to recover data from VMFS partitions. Here's how DiskInternals VMFS Recovery can be relevant in the context of UEFI booting issues:

Use Case for DiskInternals VMFS Recovery:

1. Data Recovery from Non-Booting ESXi Hosts:

  • When ESXi fails to boot due to UEFI issues, accessing the data stored on VMFS partitions can be challenging. DiskInternals VMFS Recovery can be used to access and recover this data from drives that are not bootable.

2. Corrupted VMFS Volumes:

  • If the UEFI booting issue has led to or is caused by a corrupted VMFS volume, this software can help recover the virtual machines and data stored on these volumes.

Steps for Using DiskInternals VMFS Recovery:

  1. 1. Create a Windows-based Recovery Environment:

    • Since DiskInternals VMFS Recovery runs on Windows, you'll need a separate Windows machine or a bootable Windows environment.
  2. 2. Connect the VMFS Drives:

    • Physically connect the drives containing the VMFS volumes to the Windows machine.
  3. 3. Run DiskInternals VMFS Recovery:

    • Install and open DiskInternals VMFS Recovery.
    • Follow the wizard to scan the connected drives for VMFS partitions.
  4. 4. Recover Data:

    • Once the software identifies the VMFS partitions, you can start the recovery process.
    • You can recover files, folders, or entire VMs.
  5. 5. Save Recovered Data:

    • Save the recovered data to a different location, preferably an external drive or a network location.

Limitations and Considerations:

  • Not a Boot Issue Fix: DiskInternals VMFS Recovery does not directly fix UEFI boot issues. It's a data recovery tool.
  • Windows Environment Needed: Requires a Windows-based system to run.
  • Cost: The software is not free, and significant data recovery might require purchasing a license.

While DiskInternals VMFS Recovery is an effective tool for recovering data from VMFS volumes, it's important to remember that it doesn't address the root cause of UEFI booting issues with ESXi. For resolving UEFI boot problems, other troubleshooting steps and solutions focusing on hardware compatibility, BIOS/UEFI settings, and ESXi installation integrity should be explored. DiskInternals VMFS Recovery is most useful as a means of salvaging data in situations where these issues prevent normal system booting.


In conclusion, troubleshooting UEFI booting issues with ESXi involves understanding a range of potential causes, from hardware compatibility and configuration issues to problems with the boot media or ESXi installation itself. Key steps include checking BIOS/UEFI settings, ensuring hardware compatibility, verifying the integrity of the installation media, and considering firmware updates.

When such issues lead to data accessibility problems on VMFS volumes, tools like DiskInternals VMFS Recovery can be invaluable. Although this software does not directly resolve booting issues, it serves as a critical resource for recovering data from non-bootable VMFS volumes, particularly in scenarios where UEFI booting issues have resulted in inaccessible or corrupted VMFS partitions.

The combination of thorough troubleshooting to address UEFI booting issues and leveraging specialized recovery tools for data retrieval underscores a comprehensive approach to managing and maintaining ESXi environments. Such diligence ensures not only the smooth operation of virtual infrastructures but also the safety and accessibility of crucial data in the face of booting challenges.

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