vCenter Server Appliance 6.7 U1b restore from back up fails with error 'Metadata and system validation failed.' and/or 'Failed to retrieve appliance storage list'

Products

• VMware vCenter Server

Issue/Introduction

When performing file based restore of vCenter Server Appliance 6.7, during Stage 2 of the restore process, the following errors occur :

• Metadata and system validation failed.
• Failed to retrieve appliance storage list.

When the restore fails a log bundle will be generated. 

The following is observed in the /var/log/vmware/applmgmt/applmgmt.log

YYYY-MM-DDTHH:MM:SS.663 [1387]DEBUG:util.Metadata:Proxy isn't enabled.
YYYY-MM-DDTHH:MM:SS.696 [1387]DEBUG:util.Metadata:Process returncode is 0, and expected exit codes are [0].
YYYY-MM-DDTHH:MM:SS.704 [1387]ERROR:util.Validate:Failed to get the system storage list: 'Deferred' object has no attribute 'result'

Environment

VMware vCenter Server Appliance 6.7.x

Cause

This issue occurs when the configuration of the backed up vCenter Server Appliance does not match the configuration of the vCenter Server Appliance created during Step 1 of the restore process.

Resolution

To workaround the issue.

1. Shut down the VCSA created during stage 1 of Restore process. 
2. Edit the settings of virtual machine.
   
   Ensure the following settings match the vCenter Server Appliance which was backed up:
   - CPU Hot Add
   - Memory Hot Add
   - Memory assigned 
   - Hard Disk information
   
   
3. Once the settings have been validated and updated, save the changes and power on the virtual machine.
4. Connect to restored vCenter Server Appliance on port 5480 and continue with restore.