Had a Customer where the vCenter Appliance is stuck at “Checking for updates” even after reboot. This caused if you try checking for updates without any internet.
The solution is to initiate a manual process from within the vCenter Appliance console.
1. Log into Appliance with SSH 2. /opt/vmware/bin/vamicli update –check
3. /opt/vmware/bin/vamicli update –install latest –accepteula
Hope that helps!
Solution from: https://communities.vmware.com/message/2373511