I wonder if this what you need ie do you need a proxy server setting as Mcafee will not update through it I hear
Under my browser tools/options/advanced/settings I reset it to "no proxy" right away as a part of the clean up but I missed the one under the control panel. I fought off and on for weeks until this morning I was digging around and found the other place I needed to correct:
Under control panel/internet options/connections/lan settings I unchecked proxy server.
Maybe two things
1. Read these options to fix real time scanning
2. Download both getsusp and malwarebytes and see if they find anything. getsusp will report any suspect files to Mcafee and if you provide your email addy in preferences it will update you if it finds anything. Re Malwarebytes do not install the paid version as it will calsh with Mcafee and cause the issues you see.