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How to install VMware ESXi on unsupported CPU (s)

pest_control Sympthoms
  • The installation of VMware ESXi fails with a message similar to the following:
    • 
VMB: 578:

Unsupported CPU: Intel family 0x06, model 0x1a, stepping 0x4

Intel(R) Xeon(R) CPU E5-4620 v 4 @ 2.10GHz

See http://www.vmware.com/resources/compatibility

search Causes
  • You are trying to install a version of ESXi which is not marked as supported for your hardware CPUs (refer to: VMware - Compatibility)

construction Fix/Workaround/Solution
While installing an unsupported version of ESXi may lead to compatibility issues, this doesn’t mean it’s not gonna work at all.
This could be especially useful for a “homelab”, but heavily discouraged for a production environment.

To work around the problem, follow these steps:
  1. Power off the hardware and boot into the installation media again
  2. Click SHIFT+O during the ESXi boot screen ("Loading ESXi Installer" is shown on top of the screen)
  3. Type allowLegacyCPU=true without deleting anything. It should look like this:
    4. 
<ENTER: Apply options and boot>

> cdromBoot runweasel allowLegacyCPU=true
  4. Press ENTER to continue with the installation process
  5. During the installation process you will notice a warning message similar to this:
    6. 
<CPU_SUPPORT WARNING: The CPU in this host is not supported by ESXi 7.0.0. Please refer to the VMware Compatibility Guide (VCG) for the list of supported CPUs.>
    you can simply ignore this message by pressing ENTER.
  6. You have now successfully installed VMware ESXi on an unsupported CPU!

school Further considerations
  1. This workaround is NOT permanent, as at the next startup you will need to type “allowLegacyCPU=true” during the boot process to allow ESXi to function properly.
  2. To avoid doing this every time, see How to permanently allow VMware ESXi boot on unsupported CPUs
    The prerequisite is having already installed ESXi on the system by following the steps of this guide.




Article ID: SYS-VMW-0001