Just would like to share some thoughts that I have come across during my new research.
If in future we are upgrading VMware environment to 6.0 U1b (build 3380124) then we can get a big problem for VM templates that we use to provision new systems.
As soon as VMware Tools is updated on any templates we will no longer be able to clone those templates. If we’ve updated any templates with the version of VMware Tools that comes with ESXi 6.0 U1b then we need to uninstall it and reinstall the prior version that came with ESXi 6.0 build 3247720. After the couple of reboots that we have to go through with an uninstall and reinstall of VMware Tools we will find that we can now clone VM’s and have them automatically customized.
This update just in from VMware Support “VMware Engineering have confirmed that the issue is dependent on the install/upgrade sequence. Specifically, the issue is aligned to the version of deploypkg.dll in the vmtools package. GSS and Engineering are mapping the ESX and vmtools update versions to the deploypkg.dll versions to confirm which upgrade sequences are problematic. A KB article will be published once this information is finalized.”