I am with Support and haven't heard of McAfee blocking Windows Updates. In fact McAfee has a built in component called "Vulnerability Scanner" to check for and install updates to Windows and other programs.
Please post back the version details of McAfee Total Protection installed on your computer. (Open McAfee GUI > Click "About" from bottom right)
McAfee would never block Windows Updates provided you are trying to install them using Windows/Microsoft Update. Even if they were individually downloaded all it may do is popup a check box but still wouldn't block them. Something else is at work there, Have you had any other strange happenings?
Also is this Windows 7 SP1 and do you have, even if you never use it, IE11 installed? (The reason I ask is because McAfee UI uses it).
The only time you need to disable the antivirus is when installing Service Packs and that is a very rare occasion.
I moved this to the General Discussion section.