This troubleshooting guide explains basic concepts about Virtual Machine snapshots and different troubleshooting paths depending on the problem. This guide was designed for ESX3.5 and extra considerations have to be taken if working with ESX3.5i or ESX4(i). The formulas and most of the procedures described in this document were created by Ruben as part of a continuous troubleshooting improvement process.
Ruben is also creator of SnapVMX utility.
While troubleshooting Virtual Machine (VM) snapshot problems sometimes it is important to retrieve a lot of information in order to take the most appropriate decision in accordance with the situation. That collection and arrangement of information may take a long time especially if the VM has many snapshots.
SnapVMX was created to speed up the troubleshooting process bringing you instantaneously all the information that you need to evaluate the situation and take the correct decision, reducing the downtime to the bare minimum needed to solve the problem,
Source : Eric Blog
Also Try below VMware KB TV - Consolidating snapshots (VMware KB 1007849) - video below