several do a search for " you tube"
1 such thread
Try disavbling netguard this a known issue that is being looked at
1) Open McAfee Security Center
2) Click on "Web and Email Protection"
3) Click on "Firewall"
4) Click "Net Guard"
5) Uncheck the box beside "Turn on Net Guard"
Could you please let us know since when you face this issue also with some of the below details on your Security center ;
Version of McAfee Personal Firewall :
Was McAfee purchased through the website/ cd Or is it subscribed through your ISP