SDDC Manager pre-check fails with "vSphere SHA1 validation failed" during vCenter Server upgrade

Products

• VMware SDDC Manager / VCF Installer

Issue/Introduction

• During the preparation for an SDDC Manager upgrade of vCenter Server, the pre-check fails with the following error:
  `vSphere SHA1 validation failed.

Environment

VMware vCenter Server 7.x
VMware Cloud Foundation (SDDC Manager)

Cause

The ESXi host certificate status is out of sync with the SDDC Manager. When updating to vCenter Server 8.0, support for weak signature algorithms (SHA-1) is removed. Renewing the certificate is insufficient if the cached certificate data is not explicitly refreshed on the host.

Resolution

A manual refresh of the ESXi host certificate from the vSphere Client is required to clear the SHA-1 validation failure.

1. Log in to the vSphere Client.
2. Select the target ESXi host from the inventory.
3. Navigate to *Configure* > *System* > *Certificate*.
4. Click *Renew" / Refresh CA Certificates*.
5. Select *Renew or Refresh ESXi Certificates*.
6. Retry the SDDC Manager upgrade pre-check task.