This has been gone over before in other threads, but some of the posts are old and perhaps out of date.
I started with McAfee and subscribed to their servicing. After one of their upgrades, the updates wouldn't load. I spent one whole afternoon talking to one of their technicians (in India) and we thought we corrected the problem. Came the next update, and the same problem. More talkly-talk with a differenthe Indian (these technicians seem fairly sharp and they speak good English) technician- he had the transcript of the previous "consultation"). Again, failure after a week.

I called a local service technician, and he took out the McAfee and installed Norton. I have had NO trouble since. Norton updates quietly in the background while other programs are running. Updates come almost every day, and a full check of all my programs is carried out weekly. I have had several virused emails which the program identified and isolated.
Even though the McAfee was removed, it had stuck its fingers into all sorts of things. I found one file that was still there and deleted it. When starting up, I had to punch a key to finish loading (my attention called to a McAfee program that was not there. My clock and scheduled tasks (defrag, etc.) were disrupted. A second visit by a technician last week was needed to (hopefully) remove the last traces of their system.

Oh, yes, I asked McAfee for a refund on unused contract time. Nothing ever came back to me except for renewal terms!

The technician I have here has another virus protection system that he recommends- I will ask him to call me with its name and post later. today.