Symptoms:
When setting up VMware vCenter Update Manager, you experience symptoms similar to:

• The VMware vCenter Update Manager plug-in is disabled.
  
• Enabling the VMware vCenter Update Manager plug-in results in error:
  
  There was an error connecting to VMware vSphere Update Manager - [VC-name]:443
  sysimage.fault.SSLCertificateError

VMware vCenter Update Manager 5.1.x
VMware vCenter Server 6.0.x
VMware vCenter Server 5.5.x
VMware vSphere Update Manager 5.5.x
VMware vCenter Server 5.1.x
VMware vCenter Update Manager 5.5.x

This issue occurs because VMware vCenter Update Manager requires a user account, domain or local operating system to register with its vCenter Server instance. If that vCenter Server instance is version 5.1 or 5.5 and if any disruption occurs to the SSO service where it cannot authenticate local OS or domain users, then the user account used to register VMware vCenter Update Manager with vCenter Server is unknown and, as a result, registration cannot successfully occur.

To resolve this issue:

1. If the instance is a vCenter Server 5.1 or 5.5, ensure the SSO service is started.
   
2. Ensure the correct local OS and/or AD identity sources are registered in the vSphere Web Client.
3. Go to the vCenter Update Manager install path and double-click the VMwareUpdateManagerUtility.exe file. The default install location is C:\Program Files (x86)\VMware\Infrastructure\Update Manager.
   
   Note: You must log in with a user account that is already used to log in to the vSphere Client (SSO must know the identity source in which this user is located). If you cannot log in, ensure to use an account that can sign in to vCenter Server. The user account must be able to authenticate against SSO.
   
   
4. Click Re-register to vCenter Server.
   
5. Enter credentials that SSO is able to authenticate.
   
   Note: These credentials should also have the permissions to register extensions with vCenter Server. Typically, these are users who fall into the Administrator role.
   
   
6. Restart the VMware Update Manager service.
7. Go to the vSphere Client.
   
8. Enable the plug-in.
   

This issue was originally encountered with a vCenter Server 5.1.0a build-880146 vCenter Server/VMware vCenter Update Manager instance. The SSL certs for vCenter Update Manager at C:\Program Files (x86)\VMware\Infrastructure\Update Manager\SSL were the VMware default certificates. VMware vCenter Update Manager プラグインの有効化が次のエラーで失敗する: sysimage.fault.SSLCertificateError
启用 VMware vCenter Update Manager 插件失败，并显示错误“sysimage.fault.SSLCertificateError”