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Host Integrity (HI) functionality has been included within 12.1 RU5 and newer without the need for a SNAC license. However, SNAC Enforcers will still require a SNAC license be applied to the SEPM to properly interact. Part of the SEPM upgrade process to 12.1 RU5 will require that the 12.1 RU5 SNAC Manager installation be run on the RU5 SEPM as well to fully take advantage of SNAC, beyond the Host Integrity features. Please note that a valid license is required to download, install and use the SNAC product.
The SNAC installer is available via FlexNet. Using your SEPM serial number, you will be provided with a new serial number (starting with a 'T') to log into FlexNet and acquire the install media.
https://support.symantec.com/en_US/article.TECH227131.html
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https://www-secure.symantec.com/connect/forums/snac-host-integrity-policies-not-working-if-sepm-migrated-1215-0