Ok I assume yours is not starting on time this a feature of version 11 or security centre where mcafee waits till the pC is idle for 10 muinutes before scanning. If you have version 11.6 go to navigation general settings and alerts and General settings and untick Wait until my PC is idle. Click on apply.
Is this what you mean. If you have Sc 11 well 11.6 is being rolled out now.