An important part of the configuration of any virtual machine is the time keeping. Some applications are very sensitive for having the correct time, relative to other systems. Think about Active Directory for instance.
The presentation has an overview of time keeping in VM’s. Most of the information can be found in various white papers. It is remarkable that in the presentation the usage of NTP of W32time is given as a best practise instead of using VMware Tools. This is opposed to what is written in knowledgebase article 1318 in which VMware tools are advised.
Vmware Tools is able to adjust the clock forwards but not backwards.
Knowledge base article 1318 VMware Time Sync and Windows Time Service