Symptoms:
During a supported upgrade of vCenter Server to 7.0 Update 1, you experience this symptom:

You see the Pre-upgrade check result returning back with a warning similar to:

Duplicate service registrations of the same type has been detected

VMware vCenter Server 7.0.x

This occurs due to a known issue with the Pre-upgrade check during a vCenter Server 7.0 Update 1 upgrade.

This Pre-upgrade check warning has been removed starting with VMware vSphere 7.0 Update 1c, available at VMware Downloads.

These Pre-upgrade check messages have also been removed on this version due to a known false positives which is causing the upgrade to fail to vCenter Server Update 1.

•  “SSL Trust certificate does not match the current MACHINE_SSL_CERT for one of the legacy service registrations”
• “SSL Trust certificate does not match the current MACHINE_SSL_CERT for one of the service registrations”

Note: It is possible that these Pre-upgrade checks will be reintroduced in the future to resolve internal logic issues in the product.

Workaround:
To work around this issue if you do not want to upgrade to vCenter Server 7.0 Update 1c, when using Enhanced Linked Mode in a multiple vCenter Server systems, you can safely ignore this warning by clicking on close. The upgrade should then continue.

Note: If you get this error and you are not using Enhanced Linked Mode, you must unregister the duplicate service registrations. For more information, see Find a duplicate registered vCenter Server instance. You can use the Lookup Service Doctor Tool to help you identify the duplicate service registrations.

• Pre-upgrade check result with warning and errors during upgrade to vCenter Server 7.0 Update 1 (79741)
• Using the 'lsdoctor' Tool (80469)