CentOS - Feb 2020 - vmware tools do not start on EL6 / upstart init

Hi all,

I got two CentOS6 guest vms handed over that run under VMware ESX.

After installing the missing last updates and reboots I noticed that
the vmware-tools got not started while booting 
(/etc/init/vmware-tools.conf), while manually starting works 
(/etc/vmware-tools/services.sh start). Does someone has the same 
behaviour. Any
ideas about the cause?

Thanks,
Leon