Can you post a screenshot of the exact error message? Did you ever have any security protection on your computer prior to McAfee? How much ram do you have? Do you use Internet Explorer and if so what is the version? What is your service pack? SP3 is recommended.
You could also contact Technical Support Chat found at the top of this page under Useful Links. They are available 24 hours and can remotely connect to your computer to see whats going on inside.
Along with the same can you please confirm whether your programs are McAfee home version or enterprise version ?
I am running XP/Pro and load my machine down a lot. When I do it seems that McAfee shuts down, certain parts of the security center and virus scan are turned off. Clicking FIX gets most of the problems the first time, but sometimes I have to close the McAfee screen and re-open it and try FIX again and then it seems to work. I would like to know why too.
Click on start
click on RUN
Type in services.msc
Look for McAfee McShield and make sure is it enable.
And also make sure if any thing else with Mcafee should be enable or automatic.
( Mcafee Technical Support )