The cause is a missing index on the EPOProductEventsMT database table and a large number of product client events. Often, the issue described in KB91418 - McAfee Agent 5.6 Hotfix 1264214 uploads the same events more than once and results in a backlog on the ePolicy Orchestrator server is the root cause of the excessive number of product events.

NOTE: Article KB91418 includes an SQL script to both identify and remediate the excessively duplicated events. But, as the article states, it's critical to upgrade or remove any of the existing impacted McAfee Agent versions from your environment first. Otherwise, the issue can reoccur.