When attempting to upgrade an ESXi host using vSphere Lifecycle Manager, the pre-check operation fails with an "unknown error." Investigation reveals the actual error message indicates a component downgrade issue: "The operation cannot continue due to downgrade of the following Components: [component name].
"
When you add a downgraded driver from add components section, you will get an error while saving the image that "A component downgrade was found
"
The vSphere Lifecycle Manager includes protection mechanisms that prevent inadvertent downgrades of hardware-specific components (such as drivers and firmware). When the target ESXi version would result in a component version lower than what is currently installed, this protection triggers and blocks the upgrade.
This can occur when:
esxcli software component list
` to view installed components