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The VSE 8.8 On-Demand Scan uses large amounts of memory
Technical Articles ID:   KB74927
Last Modified:  3/14/2017


McAfee VirusScan Enterprise (VSE) 8.8 with/without Patch 1 or 2


Scan32.exe or Scan64.exe uses large amounts of memory
The VSE On-Demand Scanner (ODS) architecture was improved in VSE 8.8 to be multi-threaded, so that ODS could complete in much shorter times.

To facilitate scanning, one pool of threads is reading from the hard drive to build a list of file objects to scan, and another pool of threads is removing items from that list as the file object is scanned.

Unfortunately, the list of files to scan tends to be populated faster than the scanning threads can remove items from the list. Therefore, depending on the number of files to be scanned, the list can grow (in memory) to be very large. There is no limit to the size of the list, so it can grow to multiple gigabytes in size. The size is influenced by the number of files on disk, the speed of scanning to reduce the list, and the amount of data needed to store the full path and filename of each file.

Restricting the ODS performance threshold to Very low thread priority limits the number of threads used by the ODS, but it might be insufficient to avoid this issue.

System Change

Installed VSE 8.8 and configured a scan of large volumes of files.


The list of Files to scan (in memory) grows faster than the list can be reduced by files actually being scanned.


For Windows 8 and Windows Server 2012 operating systems
This issue is resolved in VSE 8.8 Patch 3, which is available from the Product Downloads site using a valid Grant Number.

IMPORTANT: Although VSE 8.8 Patch 3 includes the code to resolve the issue, VSE 8.8 P3 is released to provide support only for Windows 8 and Windows 2012, and installs only on these two operating systems.

For all Windows operating systems
This issue is resolved in VSE 8.8 Patch 4, which is available from the Product Downloads site using a valid Grant Number. The patch is also available on the Service Portal under the Downloads tab.

NOTE: This patch release returns to supporting all supported operating systems.

Patches are cumulative; therefore, Technical Support recommends that you install the latest one. For information about the latest releases, refer to KB51111.

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

NOTE: You need a valid Grant Number for access. KB56057 provides additional information about the Product Downloads site, and alternate locations for some products.


You can control the amount of memory used by configuring ODS to target specific folders or files, rather than an entire volume or drive. In these scenarios, the number of files to be scanned will be lower, and the list of files to be scanned will not grow too much. This method requires multiple ODS tasks to scan the same volume because you are effectively breaking up a large task into smaller, more manageable, tasks.


A less complicated workaround is to use VSE 8.7i because this has only a single scan thread and does not experience the same issue.

NOTE: The time to complete the scan will be much longer than that of VSE 8.8.

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