BTW. Is it still not possible to download and save the mcafee installer? When I was messing about with it a few years ago, each time I uninstalled I had to run the re-installation from the mcafee site for each machine and was unable to save the installer. This was a hassle because at the time I had quite limited bandwidth.

Thanks for all the replies. Luckily I have my work computer at home plus various others so I'm not rushing to do anything until I've read all the superb advice here. My files etc. on the affected computer are all intact so it's not a big issue as yet. Mandrake, you say a Restore Point worked for you - what was the date that the problem update came through? Do you remember? The reason I ask is that the Security Center on mine reports May 18th, after which there was nothing more downloaded. But I was definitely on the Internet up to Thursday last week (23rd) on that computer. The update is the one that McAfee mention in their article and I'm sure it's what's caused this - just wondering why it took 5/6 days after it installed to wipe out my networking. I'm going to go with the Restore point option I think. But I do have a System Image from Win7 Backup and Restore stored on an WD external drive from two weeks ago - would that work better or would it be over the top?

System restore is best to avoid if you can.

Before going crazy with restore points and restoring backups why don't you try some of the less complicated procedures first, and then if those fail you can always do the restore then..

As requested, can you post an ipconfig here please?

I followed the advice on the McAfee site - Safe Mode with Networking then downloading and running their repair tool. It has worked and I'm now able to connect to the Internet after installing the latest McAfee updates. The recent Viruscan DAT file is 6815 by the way and users should check that they have that one. I agree that restoring backups is often fraught with danger - I did use System Restore on XP a few times and it seemed to work OK. Never tried with Win7 though.
To answer a previous question - sorry to be rude and not reply - the ipconfig stats were all fine (correct IP addresses, gateways etc.) but I couldn't ping the router (HUB3) nor connect to it via Ethernet. No pings to anywhere, in fact. It seems that this buggy update had messed up some registry entries and that's where the problem was, preventing all traffic irrespective of connections values.
One final moan - why do computer manufacturers make it so hard to get into Safe Mode? I must have tried half a dozen times to get the boot menu up - I hear it's a well-known problem with faster systems.

In reply to a post by GeoffB:

To answer a previous question - sorry to be rude and not reply - the ipconfig stats were all fine (correct IP addresses, gateways etc.) but I couldn't ping the router (HUB3) nor connect to it via Ethernet. No pings to anywhere, in fact. It seems that this buggy update had messed up some registry entries and that's where the problem was, preventing all traffic irrespective of connections values.

Modern antivirus programs insert themselves into the network stack between the operating system and the network card (either ethernet or wireless).

This is so they can watch for and detect security issues - but its one of the most critical parts of the operating system.

If the AV vendor has a bug in their code (e.g. a memory leak) this can bring the whole OS down, including blue screens. Caused by 3rd party code and not Microsoft's fault (despite the number of people who blame MS).

On the safe mode note I have heard that a few times, but never had a single problem myself. The trick is to start pressing F8 repeatedly while the computer is in the final stage of the BIOS POST, and then you are guaranteed to be pressing F8 at the right moment when needed.

A lot of people are under the impression they are only allowed to press F8 once and so inevitably fail lots of times.

The problem with system restore is that, as you know, it is designed to leave files and settings as they are but restore system and program files, so you can cause inconsistencies by using it.

After that experience, I'd be uninstalling McAfee right now!

Yes, you're right. I have a year left on this laptop (I paid for 3 via Dell when I bought it) and about 4 months on another much older computer. I'm working on the assumption that it will be 13 months at least before they c**k up again with an update so I should be safe. It seems to happen with them about once every 3 or 4 years.

I wouldn't go down the repair tool and system restore etc. route myself. If you want to keep using mcafee, which is quite understandable in your situation, then I would uninstall, use the MCPR (McAfee Consumer Product Removal Tool) and possibly use something like CCleaner to tidy up the registry, then do a fresh install of your mcafee product.

Edited by 4M2 (Sun 26-Aug-12 15:44:59)