Quick issue for you today. I was attempting to clone a RHEL 5 VM with a guest customization and the operation kept failing with: fault.CustomizationPending.summary. Turns out the VM I was attemping to clone was previously cloned with a guest customization, but was never powered on. The resolution is simply to power on the VM and once it boots up shut it down. Then you should be able to clone the VM with a guest customization without issue. VMware posted a KB article on the issue (http://kb.vmware.com/kb/1006809), but it only refers to VirtualCenter 2.5.x though I just experienced this issue on vCenter Server 4.1.
© 2011, Steve Flanders. All rights reserved.
Ah ! Yes exactly. I forgot to poweron the VM. Thanks Steve !
Glad this post helped!