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High CPU usage after a .DAT update
Technical Articles ID:   KB68965
Last Modified:  5/6/2011


McAfee VirusScan Enterprise 8.7i


The On-Access and On-Demand scanners perform certain actions after a DAT update that can cause high CPU usage until they are complete.


Poor system performance after a DAT update.

System Change

Virus definition (DAT) files were updated.


In some cases after an update, EngineServer.exe and McShield.exe both attempt to create mferuntime.dat. Each process causes the other to enter a loop of retrying to create the file and encountering sharing violations. Each attempt to create mferuntime.dat requires reading the full DAT file set again.

NOTE: Mferuntime.dat is a memory mapped file that was introduced with Patch 1 for VirusScan Enterprise (VSE) 8.7i  to assist in managing the size of the virus definition files. This file heps to maintain a smaller footprint in memory and improve scanning performance.


Patch 4 for VirusScan Enterprise 8.7i resolves this issue by changing the way the mferuntime.dat file is created.

NOTE: This issue exists only in this particular version of VirusScan Enterprise and does not exist in any other versions.

McAfee product software, upgrades, maintenance releases, and documentation are available from the Product Downloads site at: http://www.mcafee.com/us/downloads/downloads.aspx.

 You will need a valid Grant Number for access. KB56057 provides additional information about the Product Downloads site, as well as alternate locations for some products.

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