Please post the version of Mcafee? Try with netguard (a firewall setting) off. This used to help but I thought issue fixed in latest versions.
The Youtube issues in the past were all firewall caused and have been fixed by the version you are running. Best to start a support call and see what they say. they will probably suggest a reinstall their usual 1st thought and usually fixes many things.
There are no current youtube issues as far as I know. Have you checked on another PC if youtube faster. Mine seems to be fine.
Ah Chrome . Yes make a support call and for the time being use firefox or IE. I will check another mod who actually uses chrome if he has any issues.
BTW who supplies your Mcafee ie did you buy it from a store or Mcafee of say from a partner such as your ISP or Dell etc?
I ask as if it is mcafee supplied you can uninstall and get the new 12.1 version.