Hi,
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I would be glad to answer your query.
You can configure the unmanaged detector to ignore certain devices, such as printers, scanners.
In the Add Unmanaged Detector Exception dialog box, click one of the following options:
•Exclude detection of an IP address range, and then enter the IP address range for several devices.
•Exclude detection of a MAC address, and then enter the device's MAC address.
Refer this article: Configuring a client to detect unmanaged devices
http://www.symantec.com/docs/HOWTO80763