I recently used ePO to deploy VirusScan 8.7 and AntiSpyware Module 8.7 to several PCs that were running V8.5 of both products. The products we succefully deployed to all PCs. However, a handfull of them stopped reporting back to the ePO server. I depoloyed the updated products on the 24th and this now lists as the last contact date by the PCs. I tried doing an agent wake up, I tried reinstalling the agent, neither worked. The only thing that has worked was going to the PC and uninstalling all McAfee security products and re-installing. Is there anything I can try on the ePO server to remedy this without having to physically go to each PC?
checking the agent log on each client via http://computername:8081 remotely could be possible and this way you can figure out why they are not able to contact ePO server.
Also, please check if the "missing" clients are actually not reported back getting into a different group than you'd expect...