The first thing MVT does when you run it is to get the latest version from the servers. You don't (I'm pretty sure of this) actually have an MVT executable on your PC. So if it can't connect to the internet to get the latest version then of course it can't run. And what it checks isn't the state of your internet connection but the presence of all the McAfee programs, services and registry settings you need and whether they're up-to-date and set correctly.
If the initial problem started with the buggy DAT 6807, MVT was updated to fix that. You might have to run it twice to sort everything out, but it worked for almost everyone who tried it.
Please don't be unkind to the technicians who were trying to help you. I'm sure they were doing their best.
Your basic problem is a connectivity problem, right? There are tools and utilities that come as part of Windows that help you investigate this. What you've got depends on your operating system. Is it XP, Vista, Windows 7, or something else?
If you want, I can run you through a whole series of very basic steps to try and determine at what level the problem occurs. Most likely of course it's something to do with the firewall, but ruling out a few common problem areas might help.
Just to qualify what Hayton has said, I've had Support remote connect with me many a time and they have never looked at anything other than what was neeeded for their investigation, log gathering, checking settings etc. They never once opened anything personal. You can watch them on the desktop as they work. Also if the technician can't fix the problem he/she should offer to escalate the issue for you but if it seems they aren't about to do that, you can ask them to do just that. The only problem I've ever experienced was once when I couldn't understand the person (on the phone - phone support is free) but he slowed down and then I could understand him. One has to make allowances for the fact that they are in India. Of course remote support requires a working connection.
That old bad DAT issue was hairy I must admit and I was one of the first people to be hit by it. The fix came out almost immediately. If MVT couldn't fix, then uninstalling via Control Panel, running the cleanup tool (MCPR see Useful Links at the top of this page), rebooting and reinstalling could, in 99.9% of cases because the act of uninstalling restored the connection. If you are experiencing that now it's fair to assume there's another reason for it.
The problem is 100% caused by mcafee. The proof is that when I uninstall it, everything works just fine.
Ok, so mvt is useless if it can't be run without internet. And yes, there is a program that needs to be installed locally so it could have the decency of just run with whatever was the last version that it fetched.
The problem is that mcafee software is clearly not well designed and probably badly tested (assuming they actually do anything beyond a quick smoke test). An example of buggy mcafee software: their WER.exe program rejects a perfectly valid email address because it contains a "-", a perfectly valid character as per the RFCs. Although I reported the bug, 2 months later wer.exe was still broken.
Chances are that the problems were somehow triggered by whatever mvt did back in late august when I got the email from mcafee with the "fix" instructions. About 10 days later, internet was lost: all network operations fail with a "general error". FWIW, the machine is a windows 7, with an i7 cpu.
Following mcafee warped advice, I tried the uninstall and reinstall and that wasa very slippery slope where the installation failed systematically (if started from a download) or installed ok but then lost the internet shortly after (if installed from the CD). And since then, the choices have been either running without an antivirus or without internet.
The completely useless people on mcafee technical support lack basic engineering principles. Instead of trying to figure out the problem so it can be fixed, they shot in the dark hoping that one of their shots will hit something. Unfortunately, this approach is a reflection of their badly designed software that doesn't generate any useful logs that could help in identifying their bug.
For example, one of the "useful" suggestions from these useless bunch was to wipe out everything and reinstall windows! Yes, that makes sense: a lamp doesn't work at home and instead of checking the bulb or the breaker, let's bring the bulldozer and build a new house! Given this non-chalant approach to "troubleshoot" and the complete lack of guarantees on what they'll install (they absolutely refuse to disclose what any of their tools will do), I cannot grant them access: it is just too dangerous.
But enough with this. Clearly, mcafee is not what they used to be. I'll move along to some other product and forever write off mcafee.
Once I uninstall mcafee, my blood pressure will go down to normal again.
That's your choice of course.