McAfee VirusScan ships with default full scan tasks. In my environment, they show as not scheduled. These tasks cannot be managed by ePO and can run if the end-user changes them to a scheduled time. I have tested creating another local scan task and scheduled it to run as the same time of a ePO managed scan task. I saw two scan tasks running causing the system to be very slow. You need to see if these local tasks have been enabled by the end-user and have them disabled. This can't be disabled via ePO as far as I know.
we have users for whom the VSE opens in readly only mode also all items are password protected in VSE and i am pretty sure user cannot run the default local scan task. also the schedule i have checked shows disabled i mean there is no tick mark in the enable option for local scan task.