What was the version of mcafee previously installed? What is the current version?
Asking as 2011 has a firewall feature called netguard check if disabling it helps.
That said having another Av should not affect things if what I suggest does not work I can ask in our nexy=t moderator call.
Ok also run MVT from the tech support links in useful links tab above. nore session id number then contact support it is free. ask them. they will most likely ask you to uninstall reinstall Mcafee as the update could have corrupted the install.
reboot and run
Reinstall mcafee from your account