How to install ESXI 8 on an unsupported processor

Installing ESXi 8 with an Unsupported CPU

VMware ESXi 8 has discontinued support for many older CPU models, as outlined in Broadcom Article 318697 (Discontinuation and Removal of CPU Support in vSphere Versions). If you attempt to install ESXi 8 on a server with an unsupported CPU, you will receive the following error message:

VMware KB 82794 references the same Broadcom article mentioned above. The list of unsupported CPUs in VMware vSphere 8 is extensive and includes both Intel and AMD models.

Discontinued Intel CPU Support in VMware vSphere 8.0x:

Discontinued AMD CPU Support in VMware vSphere 8.0x:

This list does not cover all desktop/laptop CPUs. If you are looking to install ESXi 8 in a lab environment, how can you bypass the CPU check?

Important: Installing ESXi 8 on an unsupported processor is not recommended for production environments.

Bypassing the CPU Check During Boot:

1. Boot the system from the ESXi installation media.
2. When the “Loading ESXi Installer” message appears, press SHIFT+O within 5 seconds.
3. Add the following option at the end of the boot line:

   allowLegacyCPU=true
   

4. Press Enter to apply and proceed with installation.

Be aware that issues may still arise.

Additional ESXi 8.0 Update 2 CPU Requirements:

• ESXi 8.0 Update 2 requires CPUs supporting the XSAVE instruction.
• If your CPU does not support XSAVE, you cannot upgrade and must use at least an Intel Sandy Bridge or AMD Bulldozer processor.
• While interactive installation works, automated Kickstart installations may fail since manual confirmation is required.

Automating the Bypass with Kickstart Scripts:

To automate installations and bypass warnings/errors, you can add the following options to your Kickstart script:

• --ignoreprereqwarnings → Ignores warning messages.
• --ignoreprereqerrors → Ignores error messages.
• --forceunsupportedinstall → Bypasses all errors/warnings for deprecated CPUs.

Upcoming vSphere 9.0 CPU Deprecations:

The next major vSphere release (9.0) will drop support for additional CPU families, including:

• Intel Skylake Processors: Intel has moved Skylake CPUs to End of Servicing Update (ESU) / End of Servicing Lifetime (EOSL) as of December 31, 2023. Consequently, VMware plans to remove support for Intel Skylake family CPUs in vSphere versions beyond 8.0.x.

For future updates and detailed CPU support information, refer to VMware’s official documentation.