Hi I was using SEPM and NAC MR6MP3. I decided to upgrade to version 12!!! after upgrading SEPM and NAC to version 12 and assigning packages to the groups, I checked some clients,All SEP features like Antivirus,Sonar and NTP was running but Network Access Control (NAC) feature was not available and running on them. I checked some documents about SEP 12 and it is a known issue in SEP 12 and unfortunately for me in NAC! http://www.symantec.com/business/support/index?page=content&id=TECH164677 The issue occurs under the following conditions in upgrade process. 1. You have an 11.x SEPM with packages assigned to the groups. 2. The packages have "Maintain existing client features when updating" unchecked The solutions in this article didn't solve my problem in NAC feature. the solution that solved my problem in Network Access Control: 1-I created some new groups in SEPM 2-I moved clients with this issue to the new groups(Those clients which Network Access Control was not available on them). 3-I Uncheckd the maintain existing features checkbox and specify the client features i wanted to be installed on them. 4-Network Access Control feature is now running on these clients 5-life is beautiful. Thanks