ESXi Boot-up Issue: Fatal Error 6 (Buffer Too Small)
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ESXi Boot-up Issue: Fatal Error 6 (Buffer Too Small)

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Article ID: 301480

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

When booting an ESXi host, the following error message may appear, causing the system to fail during startup:

Error loading /epsec_mu.v00  Compressed MD5: 2eedadc558e36a086543f18e9e423fd9  Decompressed MD5: 000000000000000000000000000  Fatal error: 6 (Buffer too small).

Environment

  • VMware vSphere Esxi 7.x
  • VMware vSphere Esxi 8.x 

Cause

The Fatal error: 6 (Buffer too small) indicates corruption in the boot bank. This corruption can occur due to various reasons, such as:

  • An incomplete or failed ESXi upgrade.
  • File system corruption.
  • Disk or hardware issues affecting the boot bank.

Resolution

Option A: Revert ESXi to the Last Known Good Boot State

  1. If the system has successfully booted previously, you can attempt to revert to the last known good configuration.
  2. Follow the steps in KB article: Reverting to a previous version of ESXi to revert the ESXi system to its last stable state.
    • Ensure you select the correct boot bank from the available options, and choose the last working version of ESXi.

Option B: Reinstall ESXi

If reverting to the previous boot state doesn’t resolve the issue, the next step is to reinstall ESXi. Follow these steps:

  1. Backup any critical data or configuration, if possible, before reinstalling ESXi.
  2. Download the latest ESXi installation media for your version (7.x, or 8.x).
  3. Boot the ESXi host from the installation media.
  4. Select Install and follow the on-screen prompts to reinstall ESXi.
  5. Once the installation is complete, configure the ESXi host as needed.

Additional Information

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