Steps to reset the Update Manager Database
Note: Please take a Snapshot of VCSA before following below steps:
1. Connect vCSA via SSH.service-control --stop vmware-updatemgr
3. Run the following command to reset the VMware Update Manager Database:
vCenter Server Appliance 6.5 : /usr/lib/vmware-updatemgr/bin/updatemgr-util reset-db
vCenter Server Appliance 6.7: /usr/lib/vmware-updatemgr/bin/updatemgr-utility.py reset-db
service-control --start vmware-updatemgr
6. Log out and log back in to the vSphere Web Client.