Booting vSphere ESXi 8.0 may fail with "Error 10 (Out of resources)"

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• Hardware machine is configured to boot in legacy BIOS mode.
• Booting stops early in the boot process with messages displayed in red on black with wording similar to "Error 10 (Out of resources) while loading module", "Requested malloc size failed", or "No free memory".

 

Environment

VMware vSphere ESXi 8.0.0

Cause

When hardware machine boots in legacy BIOS mode, only a small portion of its memory is available for the bootloader to use. The exact amount depends on the machine's hardware configuration. If too little memory is available, booting may fail  with "Out of resources" or other similar messages.

Resolution

VMware has deprecated the use of legacy BIOS and supports it only on a best-efforts basis. VMware Engineering will not be making any changes to our legacy BIOS boot code to try to overcome the memory limitations of legacy BIOS mode. To resolve this issue, change to UEFI mode.

For more information, see Deprecation of legacy BIOS support in vSphere (84233)

Workaround:
VMware's recommended workaround is to transition the machine to UEFI boot mode permanently, as discussed in KB article 84233 . There will not be a future ESXi change to allow legacy BIOS to work on this machine again.