Network performance slows significantly after installing Symantec AntiVirus Corporate Edition

Situation:

When Symantec AntiVirus Corporate Edition clients have Auto-Protect or Realtime Protection enabled, copying and editing files on a mapped network drive slows significantly.

Solution:
This problem occurs when Symantec AntiVirus scans network drives unnecessarily. Follow the directions for your product version.

Symantec AntiVirus 10.1 and Symantec Client Security 3.1
To fix the problem, you may need to change the Networking Scanning Options, or you may need to disable network scans.
For directions, read About Network Scanning Options in Symantec AntiVirus 10.1 and Symantec Client Security 3.1.


Symantec AntiVirus 10.0 and Symantec Client Security 3.0 or earlier
To fix the problem, disable network scans.

To solve this problem in a managed environment

  1. Start Symantec System Center.
  2. Unlock the server group.
  3. Right-click the server group, and then click All Tasks > Symantec AntiVirus > Client Realtime Protection Options or Client Auto-Protect Options.
  4. Under Drive types, uncheck Network.
  5. Click the lock icon next to the Network check box so that it appears as locked.
    Locking the option prevents users from changing the option on the workstations.



     
  6. Click Reset All, and then click OK.
  7. Right-click the server group, click All Tasks > Symantec AntiVirus > Server Realtime Protection Options or Server Auto-Protect Options.
  8. Under Drive types, uncheck Network.
  9. Click OK.


In an unmanaged environment, you must configure each client not to scan network drives.

To solve this problem in an unmanaged environment

  1. Start Symantec AntiVirus.
  2. Click Configure.
  3. Click File System Realtime Protection or File System Auto-Protect.
  4. Under Drive types, uncheck Network.
  5. Click OK.




Technical Information:
When multiple clients copy or edit documents on a mapped network drive, each client downloads and scans each document that is accessed. This includes not only the documents that the user accesses, but any file accessed by the system. For example, if a user hovers the mouse pointer over a file listing in Windows Explorer, Explorer accesses the file in order to display file properties in a ToolTip, which triggers a scan. The cumulative effect of users with network drive scanning enabled can slow network traffic significantly, and is not necessary if the file server has virus protection.