Not without causuing all kinds of problems and it isn't McAfee that's preventing it. Something must not have installed properly or you overlooked something asking permission to continue perhaps?
Whatever Metro app isn't working have you open McAfee Firewall settings to check if it has the appropriate permission?
You might want to contact Technical Support on this as they can fix whatever is wrong I am sure.
See the link under Useful Links at the top of this page - it's free by phone or online chat.
In my Windows 8 I have no issues whatsoever with the Metro screen so they should be able to troubleshoot it.